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Transcript
02 Forces and Motion 335 minutes 335 marks Q1. (a) When a car is driven efficiently the engine gives a constant forward pull on the car as the car accelerates to its maximum speed. During this time frictional forces and air resistance oppose the forward motion of the car. The sketch graphs below show how the car’s speed increases when only the driver is in the car, and when the driver has a passenger in the car. (i) How does the acceleration of the car change with time? ........................................................................................................................... ........................................................................................................................... (1) (ii) What conclusion can be made about the resultant (net) forward force on the car as its speed increases? ........................................................................................................................... ........................................................................................................................... (1) (ii) On the graph, draw a line to show how you would expect the car’s speed to vary if it carried three passengers. (1) (b) The manufacturer of a family car gave the following information. Mass of car 950g The car will accelerate from 0 to 33 m/s in 11 seconds. (i) Calculate the acceleration of the car during the 11 seconds. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... Answer ..................................................... (2) (ii) Calculate the force needed to produce this acceleration. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... Answer .................................. N (2) (iii) The manufacturer of the car claims a top speed of 110 miles per hour. Explain why there must be a top speed for any car. ........................................................................................................................... ........................................................................................................................... (2) (Total 9 marks) Q2. The manufacturer of a family car gave the following information. Mass of car 950 kg The car will accelerate from 0 to 33 m/s in 11 seconds. (a) Calculate the acceleration of the car during the 11 seconds. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (b) Calculate the force needed to produce this acceleration. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (c) The manufacturer of the car claims a top speed of 110 miles per hour. Explain why there must be a top speed for any car. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (Total 7 marks) Q3. The table contains typical data for an oil tanker. (i) Write down the equation which links acceleration, force and mass. ..................................................................................................................................... (1) (ii) Calculate the deceleration of the oil tanker. Show clearly how you work out your answer. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Deceleration = ............................ m/s2 (2) (Total 3 marks) Q4. (a) A shopping trolley is being pushed at a constant speed. The arrows represent the horizontal forces on the trolley. (i) How big is force P compared to force F? .......................................................................................................................... (1) (ii) Which one of the distance-time graphs, K, L or M, shows the motion of the trolley? Draw a circle around your answer. (1) (b) Complete the sentence by crossing out the two words in the box that are wrong. Acceleration is the rate of change of (1) (c) Three trolleys, A, B and C, are pushed using the same size force. The force causes each trolley to accelerate. Which trolley will have the smallest acceleration? .................................................................................................................................... Give a reason for your answer. .................................................................................................................................... (2) (Total 5 marks) ## The table shows the braking distances for a car at different speeds and kinetic energy. The braking distance is how far the car travels once the brakes have been applied. (a) Braking distance in m Speed of car in m/s Kinetic energy of car in kJ 5 10 40 12 15 90 20 20 160 33 25 250 45 30 360 A student suggests, “the braking distance is directly proportional to the kinetic energy.” (i) Draw a line graph to test this suggestion. (3) (ii) Does the graph show that the student’s suggestion was correct or incorrect? Give a reason for your answer. .......................................................................................................................... .......................................................................................................................... (1) (iii) Use your graph and the following equation to predict a braking distance for a speed of 35 metres per second (m/s). The mass of the car is 800 kilograms (kg). Show clearly how you obtain your answer. kinetic energy = ½ mv2 .......................................................................................................................... .......................................................................................................................... Braking distance = ........................................ m (2) (iv) State one factor, apart from speed, which would increase the car’s braking distance. .......................................................................................................................... (1) (b) The diagram shows a car before and during a crash test. The car hits the wall at14 metres per second (m/s) and takes 0.25 seconds (s) to stop. (i) Write down the equation which links acceleration, change in velocity and time taken. .......................................................................................................................... (1) (ii) Calculate the deceleration of the car. .......................................................................................................................... Deceleration = ........................................ m/s2 (1) (iii) In an accident the crumple zone at the front of a car collapses progressively. This increases the time it takes the car to stop. In a front end collision the injury to the car passengers should be reduced. Explain why. The answer has been started for you. By increasing the time it takes for the car to stop, the ................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (2) (Total 11 marks) Q6. A cyclist goes on a long ride. The graph shows how the distance travelled changes with time during the ride. (i) Between which two points on the graph was the cyclist moving at the fastest speed? ..................................................................................................................................... (1) (ii) State one way cyclists can reduce the air resistance acting on them. ..................................................................................................................................... ..................................................................................................................................... (1) (iii) How long did the cyclist stop and rest? ..................................................................................................................................... (1) (iv) Write down the equation which links distance, speed and time. ..................................................................................................................................... (1) (v) Calculate, in km/hr, the average speed of the cyclist while moving. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Average speed = .............................. km/hr (3) (Total 7 marks) Q7. The graph shows how the distance travelled by a car changes with time during a short journey. (i) Describe fully the motion of the car during the first two minutes of the journey. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (ii) During the last minute of the journey the velocity of the car changes although the speed remains constant. How is this possible? ..................................................................................................................................... ..................................................................................................................................... (1) (Total 4 marks) Q8. The diagram shows an orbiter, the reusable part of a space shuttle. The data refers to a typical flight. (a) (i) What name is given to the force which keeps the orbiter in orbit around the Earth? ........................................................................................................................ (1) (ii) Use the following equation to calculate the kinetic energy, in joules, of the orbiter while it is in orbit. kinetic energy = ½ mv2 .......................................................................................................................... .......................................................................................................................... Kinetic energy = ............................. joules (2) (iii) What happens to most of this kinetic energy as the orbiter re-enters the Earth’s atmosphere? ........................................................................................................................ ........................................................................................................................ (1) (b) After touchdown the orbiter decelerates uniformly coming to a halt in 50 s. (i) Give the equation that links acceleration, time and velocity. ........................................................................................................................ (1) (ii) Calculate the deceleration of the orbiter. Show clearly how you work out your answer and give the unit. ........................................................................................................................... ........................................................................................................................... Deceleration = ............................... (2) (c) (i) Give the equation that links acceleration, force and mass. ........................................................................................................................... (1) (ii) Calculate, in newtons, the force needed to bring the orbiter to a halt. Show clearly how you work out your answer. ........................................................................................................................... ........................................................................................................................... Force = ............................ newtons (1) (Total 9 marks) Q9. (a) (i) The diagram shows the horizontal forces that act on a moving motorbike. Describe the movement of the motorbike when force A equals force B. ........................................................................................................................... ........................................................................................................................... (2) (ii) What happens to the speed of the motorbike if force B becomes smaller than force A? ........................................................................................................................... (1) (b) The graph shows how the velocity of a motorbike changes when it is travelling along a straight road. (i) What was the change in velocity of the motorbike in the first 5 seconds? ........................................................................................................................... (1) (ii) Write down the equation which links acceleration, change in velocity and time taken. ........................................................................................................................... (1) (iii) Calculate the acceleration of the motorbike during the first 5 seconds. Show clearly how you work out your answer and give the unit. ........................................................................................................................... ........................................................................................................................... Acceleration = ............................................. (3) (c) A car is travelling on an icy road. Describe and explain what might happen to the car when the brakes are applied. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (d) Name three factors, other than weather conditions, which would increase the overall stopping distance of a vehicle. 1 .................................................................................................................................. ..................................................................................................................................... 2 .................................................................................................................................. ..................................................................................................................................... 3 .................................................................................................................................. ..................................................................................................................................... (3) (Total 13 marks) Q10. The distance-time graph represents the motion of a car during a race. (a) Describe the motion of the car between point A and point D. You should not carry out any calculations. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (b) Calculate the gradient of the graph between point B and point C. Show clearly how you get your answer. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... gradient = ........................................................................ (3) (Total 6 marks) Q11. (a) The arrows in the diagram represent the size and direction of the forces on a space shuttle, fuel tank and booster rockets one second after launch. The longer the arrow the bigger the force. Thrust force Weight of shuttle, fuel tanks and booster rockets plus air resistance (i) Describe the upward motion of the space shuttle one second after launch. ........................................................................................................................... (1) (ii) By the time it moves out of the Earth’s atmosphere, the total weight of the space shuttle, fuel tank and booster rockets has decreased and so has the air resistance. How does this change the motion of the space shuttle? (Assume the thrust force does not change). ........................................................................................................................... (1) (b) The space shuttle takes 9 minutes to reach its orbital velocity of 8100 m/s. (i) Write down the equation that links acceleration, change in velocity and time taken. ........................................................................................................................... (1) (ii) Calculate, in m/s2, the average acceleration of the space shuttle during the first 9 minutes of its flight. Show clearly how you work out your answer. ........................................................................................................................... ........................................................................................................................... average acceleration = .............................................. m/s2 (2) (iii) How is the velocity of an object different from the speed of an object? ........................................................................................................................... ........................................................................................................................... (1) (Total 6 marks) Q12. A horse and rider take part in a long distance race. The graph shows how far the horse and rider travel during the race. (a) What was the distance of the race? distance = .................................................................. km (1) (b) How long did it take the horse and rider to complete the race? ..................................................................................................................................... (1) (c) What distance did the horse and rider travel in the first 2 hours of the race? distance = .................................................................. km (1) (d) How long did the horse and rider stop and rest during the race? ..................................................................................................................................... (1) (e) Not counting the time it was resting, between which two points was the horse moving the slowest? ................................. and .................................. Give a reason for your answer. ..................................................................................................................................... ..................................................................................................................................... (2) (Total 6 marks) Q13. A car travelling along a straight road has to stop and wait at red traffic lights. The graph shows how the velocity of the car changes after the traffic lights turn green. (a) Between the traffic lights changing to green and the car starting to move there is a time delay. This is called the reaction time. Write down one factor that could affect the driver’s reaction time. ..................................................................................................................................... (1) (b) Calculate the distance the car travels while accelerating. Show clearly how you work out your answer. ..................................................................................................................................... ..................................................................................................................................... Distance = ...............................................metres (3) (c) Calculate the acceleration of the car. Show clearly how you work out your final answer and give the units. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Acceleration = ................................................................... (4) (d) The mass of the car is 900 kg. (i) Write down the equation that links acceleration, force and mass. .......................................................................................................................... (1) (ii) Calculate the force used to accelerate the car. Show clearly how you work out your final answer. .......................................................................................................................... .......................................................................................................................... Force = ..................................................... newtons (2) (Total 11 marks) Q14. A car and a bicycle are travelling along a straight road. They have stopped at road works. The graph shows how the velocity of the car changes after the sign is changed to GO. (a) Between which two points on the graph is the car moving at constant velocity? ..................................................................................................................................... (1) (b) Between which two points on the graph is the car accelerating? ..................................................................................................................................... (1) (c) Between the sign changing to GO and the car starting to move, there is a time delay. This is called the reaction time. (i) What is the reaction time of the car driver? Reaction time = ................................. seconds (1) (ii) Which one of the following could increase the reaction time of a car driver? Tick the box next to your choice. Drinking alcohol Wet roads Worn car brakes (1) (d) The cyclist starts to move at the same time as the car. For the first 2 seconds the cyclist’s acceleration is constant and is greater than that of the car. Draw a line on the graph to show how the velocity of the cyclist might change during the first 2 seconds of its motion. (2) (Total 6 marks) Q15. A car is driven along a straight road. The graph shows how the velocity of the car changes during part of the journey. (a) Use the graph to calculate the deceleration of the car between 6 and 9 seconds. Show clearly how you work out your answer and give the unit. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... Deceleration = ................................................. (3) (b) At what time did the car change direction? .................................. seconds (1) (Total 4 marks) Q16. The diagram shows the forces on a small, radio-controlled, flying toy. (a) (i) The mass of the toy is 0.06 kg. Gravitational field strength = 10 N/kg Use the equation in the box to calculate the weight of the toy. weight = mass × gravitational field strength Show clearly how you work out your answer and give the unit. .......................................................................................................................... .......................................................................................................................... Weight = ................................................. (3) (ii) Complete the following sentence by drawing a ring around the correct line in the box. When the toy is hovering stationary in mid-air, the lift force is bigger than the same the weight of the toy. as smaller than (1) (b) When the motor inside the toy is switched off, the toy starts to accelerate downwards. (i) What does the word accelerate mean? .......................................................................................................................... (1) (ii) What is the direction of the resultant force on the falling toy? .......................................................................................................................... (1) (iii) Does the momentum of the toy increase, decrease or stay the same? .......................................................................................................................... Give a reason for your answer. .......................................................................................................................... (2) (Total 8 marks) Q17. In an experiment at an accident research laboratory, a car driven by remote control was crashed into the back of an identical stationary car. On impact the two cars joined together and moved in a straight line. (a) The graph shows how the velocity of the remote-controlled car changed during the experiment. (i) How is the velocity of a car different from the speed of a car? ........................................................................................................................... (1) (ii) Use the graph to calculate the distance travelled by the remote-controlled car before the collision. Show clearly how you work out your answer. ........................................................................................................................... ........................................................................................................................... Distance = ............................................... m (2) (iii) Draw, on the grid below, a graph to show how the velocity of the second car changed during the experiment. (2) (iv) The total momentum of the two cars was not conserved. What does this statement mean? ........................................................................................................................... ........................................................................................................................... (1) (b) The graph line shows how the force from a seat belt on a car driver changes during a collision. Scientists at the accident research laboratory want to develop a seat belt that produces a constant force throughout a collision. Use the idea of momentum to explain why this type of seat belt would be better for a car driver. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (Total 8 marks) Q18. Part of a bus route is along a high street.The distance – time graph shows how far the bus travelled along the high street and how long it took. (a) The bus travels the slowest between points D and E. How can you tell this from the graph? ..................................................................................................................................... ..................................................................................................................................... (1) (b) Between which two points was the bus travelling the fastest? Put a tick ( ) in the box next to your answer. Points A–B B–C C–D (1) (c) There is a bus stop in the high street.This is marked as point B on the graph. (i) What is the distance between point A on the graph and the bus stop? Distance .............................. metres (1) (ii) How long did the bus stop at the bus stop? Show clearly how you work out your answer. ........................................................................................................................... Time = .............................. seconds (2) (d) A cyclist made the same journey along the high street. The cyclist started at the same time as the bus and completed the journey in 200 seconds. The cyclist travelled the whole distance at a constant speed. (i) Draw a line on the graph to show the cyclist’s journey. (2) (ii) After how many seconds did the cyclist overtake the bus? The cyclist overtook the bus after .............................. seconds. (1) (Total 8 marks) Q19. (a) The diagram shows an athlete at the start of a race. The race is along a straight track. In the first 2 seconds, the athlete accelerates constantly and reaches a speed of 9 m/s. (i) Use the equation in the box to calculate the acceleration of the athlete. Show clearly how you work out your answer. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... Acceleration = .............................. (2) (ii) Which one of the following is the unit for acceleration? Draw a ring around your answer. J/s m/s m/s2 Nm (1) (iii) Complete the following sentence. The velocity of the athlete is the .................................................................... of the athlete in a given direction. (1) (iv) Complete the graph to show how the velocity of the athlete changes during the first 2 seconds of the race. (2) (b) Many running shoes have a cushioning system. This reduces the impact force on the athlete as the heel of the running shoe hits the ground. The bar chart shows the maximum impact force for three different makes of running shoe used on three different types of surface. (i) Which one of the three makes of running shoe, A, B or C, has the best cushioning system? ........................................................................................................................... Explain the reason for your answer. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (3) (ii) The data needed to draw the bar chart was obtained using a robotic athlete fitted with electronic sensors. Why is this data likely to be more reliable than data obtained using human athletes? ........................................................................................................................... ........................................................................................................................... (1) (Total 10 marks) Q20.(a) The diagram shows four vehicles, A, B, C and D, travelling along a road. (i) Which two of the vehicles, A, B, C or D, have the same velocity? Write your answers in the boxes. and Give the reason for your answer. ............................................................................................................... ............................................................................................................... (2) (ii) Each of the quantities in the box is either a scalar or a vector quantity. acceleration distance momentum force time kinetic energy weight Complete the table by writing each of the quantities in the box in the correct column. One has already been done for you. Vector quantity Scalar quantity force ........................................ ....................................... ....................................... ....................................... ....................................... ....................................... ....................................... ....................................... ....................................... (6) (b) A student investigated how the average speed of a trolley depends on the force applied to it. The diagram shows the trolley just before the student released it. After releasing the trolley the student measured the time it took for the trolley to travel 1 metre. The student repeated this with different weights attached to the string. (i) The measurements taken by the student were not accurate. Which two of the following would cause an error in the student’s measurements? Tick ( ) two boxes. The front of the trolley is not level with the end of the metre rule. The string is rubbing against the front of the runway. The stop clock has not been reset to zero. The force is found by counting the weights tied to the string. (2) (ii) Having calculated the average speed, the student plotted the graph shown below. Describe the pattern that links the average speed of the trolley and the force applied to the trolley. ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (c) The diagram shows the horizontal forces acting on a car as it moves along a straight road. The resultant force on the car is zero. (i) What is meant by the term resultant force? ............................................................................................................... ............................................................................................................... (1) (ii) Describe the movement of the car when the resultant force is zero. ............................................................................................................... ............................................................................................................... (1) (d) A resultant force of 3600 N, acting on a car and its driver, causes the car to accelerate at 3 m/s2. Calculate the mass, in kilograms, of the car and the driver. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ Mass = ............................................................ kg (2) (e) The graphs show how the velocities of two cars, A and B, change from the moment the car drivers see an obstacle blocking the road. Compare and evaluate the information shown in the two graphs. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (6) (f) In a road accident test laboratory, scientists use sensors to measure the forces exerted during collisions. The graphs show how the electrical resistance of 3 experimental types of sensor, X, Y andZ, change with the force applied to the sensor. Which of the sensors, X, Y or Z, would be the best one to use as a force sensor? Write your answer in the box. Give reasons for your answer. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (Total 25 marks) Q21.(a) Complete the sentence. In a closed system, when two objects collide, the total momentum of the two objects before the collision is ...................................................................................... the total momentum of the two objects after the collision. (1) (b) The diagram shows a car before and after the car collides with a stationary van. The handbrake of the van is not on. Use the information in the diagram to calculate the velocity, v, in metres per second, with which the van moves forwards after the collision. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ Velocity = ........................................................ m/s (4) (c) The graph shows the velocity of the car before, during and after the collision. Use the graph to calculate the distance travelled by the car, in metres, after the collision. ........................................................................................................................ ........................................................................................................................ Distance = ............................................ m (2) (d) The collision causes the car driver to jerk forward. Explain why wearing a seat belt reduces the risk of the driver being injured in the collision. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (Total 10 marks) Q22. A car is driven along a straight, snow covered, road. The graph shows how the velocity of the car changes from the moment the driver sees a very slow moving queue of traffic ahead. (a) Use the graph to calculate the distance the car travels while it is slowing down. Show clearly how you work out your answer. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ Distance = ....................................... m (3) (b) The car has a mass of 1200 kg. Calculate the kinetic of the car when it travels at a speed of 12 m/s. Write down the equation you use, and then show clearly how you work out your answer. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ Kinetic energy = ....................................... J (2) (Total 5 marks) Q23. The diagram shows the horizontal forces acting on a car of mass 1200 kg. (a) Calculate the acceleration of the car at the instant shown in the diagram. Write down the equation you use, and then show clearly how you work out your answer and give the unit. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ Acceleration = ............................. (4) (b) Explain why the car reaches a top speed even though the thrust force remains constant at 3500 N. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (c) The diagram shows a car and a van. The two vehicles have the same mass and identical engines. Explain why the top speed of the car is higher than the top speed of the van. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (4) (Total 11 marks) Q24. The graphs in List A show how the velocities of three vehicles change with time.The statements in List B describe different motions. Draw one line from each graph in List A to the description of the motion represented by that graph in List B. List A Velocity–time graphs List B Descriptions of motion (Total 3 marks) Q25. A cyclist travelling along a straight level road accelerates at 1.2 m/s2 for 5 seconds. The mass of the cyclist and the bicycle is 80 kg. (a) Use the equation in the box to calculate the resultant force needed to produce this acceleration. resultant force = mass × acceleration Show clearly how you work out your answer and give the unit. ........................................................................................................................ ........................................................................................................................ Resultant force = ........................................... (3) (b) The graph shows how the velocity of the cyclist changes with time. (i) Complete the following sentence. The velocity includes both the speed and the ........................of the cyclist. (1) (ii) Why has the data for the cyclist been shown as a line graph instead of a bar chart? ............................................................................................................... ............................................................................................................... (1) (iii) The diagrams show the horizontal forces acting on the cyclist at three different speeds. The length of an arrow represents the size of the force. A B C Which one of the diagrams, A, B or C, represents the forces acting when the cyclist is travelling at a constant 9 m/s? ............................................................................................................... Explain the reason for your choice. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (3) (Total 8 marks) Q26.The arrows in the diagram represent the horizontal forces acting on a motorbike at one moment in time. (a) The mass of the motorbike and rider is 275 kg. Use the equation in the box to calculate the acceleration of the motorbike at this moment in time. resultant force = mass × acceleration Show clearly how you work out your answer. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ Acceleration = ............................................................ m/s2 (3) (b) A road safety organisation has investigated the causes of motorbike accidents. The main aim of the investigation was to find out whether there was any evidence that young, inexperienced riders were more likely to be involved in an accident than older, experienced riders. Data obtained by the organisation from a sample of 1800 police files involving motorbike accidents, is summarised in the table. Size of motorbikeengine Percentage of allmotorbikes sold Total number inthe sample of 1800accident files up to 125 cc 36 774 126 to 350 cc 7 126 351 to 500 cc 7 162 over 500 cc 50 738 Most of the motorbikes with engines up to 125 cc were ridden by young people.The motorbikes with engines over 500 cc were ridden by older, more experienced riders. (i) In terms of the main aim of the investigation, is this data valid? Draw a ring around your answer. NO YES Explain the reason for your answer. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (ii) The organisation concluded that: “Young, inexperienced riders are more likely to be involved in a motorbike accident than older, experienced riders”. Explain how the data supports this conclusion. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (c) Of particular concern to motorbike riders is the design of steel crash barriers. Riders falling off and sliding at high speed into a steel support post are often seriously injured. One way to reduce the risk of serious injury is to cover the post in a thick layer of high impact polyurethane foam. (i) Use the ideas of momentum to explain how the layer of foam reduces the risk of serious injury to a motorbike rider sliding at high speed into the support post. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (3) (ii) Crash barrier tests use dummies that collide at 17 m/s with the barrier. Each test costs about £12 000. New safety devices for crash barriers are tested many times to make sure that they will improve safety. Do you think that the cost of developing the new safety devices is justified? Draw a ring around your answer. NO YES Give a reason for your answer. ............................................................................................................... ............................................................................................................... (1) (Total 11 marks) Q27. The diagram shows the velocity-time graph for an object over a 10 second period. (a) Use the graph to calculate the distance travelled by the object in 10 seconds. Show clearly how you work out your answer. ........................................................................................................................ ........................................................................................................................ Distance = ............................................................ m (2) (b) Complete the distance-time graph for the object over the same 10 seconds. (2) (Total 4 marks) Q28. (a) (i) The diagram shows three vehicles travelling along a straight road at 14 m/s. Which vehicle has the greatest momentum? ............................................................ Give the reason for your answer. ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (ii) Use the equation in the box to calculate the momentum of the motorbike when it travels at 14 m/s. momentum = mass × velocity Show clearly how you work out your answer. ............................................................................................................... ............................................................................................................... Momentum = ............................................................kg m/s (2) (b) The motorbike follows the lorry for a short time, and then accelerates to overtake both the lorry and van. (i) Complete the following sentence by drawing a ring around the correct line in the box. When the motorbike starts to overtake, the kinetic energy decreases. of the motorbike stays the same. increases. (1) (ii) Give a reason for your answer to part (b)(i). ............................................................................................................... ............................................................................................................... (1) (iii) The graph shows the velocity of the motorbike up to the time when it starts to accelerate. The motorbike accelerates constantly, going from a speed of 14 m/s to a speed of 20 m/s in a time of 2 seconds. The motorbike then stays at 20 m/s. Complete the graph to show the motion of the motorbike over the next 4 seconds. (3) (Total 9 marks) Q29. (a) The diagram shows the horizontal forces acting on a swimmer. (i) The swimmer is moving at constant speed. Force T is 120 N. What is the size of force D? .................................................. N (1) (ii) By increasing force T to 140 N, the swimmer accelerates to a higher speed. Calculate the size of the initial resultant force acting on the swimmer. ............................................................................................................... ............................................................................................................... Initial resultant force = .................................................. N (1) (iii) Even though the swimmer keeps the force T constant at 140 N, the resultant force on the swimmer decreases to zero. Explain why. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (3) (b) A sports scientist investigated how the force exerted by a swimmer’s hands against the water affects the swimmer’s speed.The investigation involved 20 males and 20 females swimming a fixed distance.Sensors placed on each swimmer’s hands measured the force 85 times every second over the last 10 metres of the swim.The measurements were used to calculate an average force.The average speed of each swimmer over the last 10 metres of the swim was also measured. The data from the investigation is displayed in the graph. (i) What was the dependent variable in this investigation? ............................................................................................................... (1) (ii) Explain one advantage of measuring the force 85 times every second rather than just once or twice every second. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... (2) (iii) Give one way in which the data for the male swimmers is different from the data for the female swimmers. ............................................................................................................... ............................................................................................................... (1) (iv) Considering only the data from this investigation, what advice should a swimming coach give to swimmers who want to increase their average speed? ............................................................................................................... ............................................................................................................... (1) (Total 10 marks) Q30. A high-speed train accelerates at a constant rate in a straight line. The velocity of the train increases from 30 m/s to 42 m/s in 60 seconds. (a) (i) Calculate the change in the velocity of the train. ............................................................................................................... Change in velocity = .............................. m/s (1) (ii) Use the equation in the box to calculate the acceleration of the train. Show clearly how you work out your answer and give the unit. Choose the unit from the list below. m/s m/s2 N/kg Nm ............................................................................................................... ............................................................................................................... Acceleration = .................................................. (2) (b) Which one of the graphs, A, B or C, shows how the velocity of the train changes as it accelerates? Write your answer, A, B or C, in the box. A B C Graph (1) (Total 4 marks) Q31.The diagram shows the forces acting on a car. The car is being driven along a straight, level road at a constant speed of 12 m/s. (a) The driver then accelerates the car to 23 m/s in 4 seconds. Use the equation in the box to calculate the acceleration of the car. Show clearly how you work out your answer and give the unit. ........................................................................................................................ ........................................................................................................................ Acceleration = ................................................................................... (3) (b) Describe how the horizontal forces acting on the car change during the first two seconds of the acceleration. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (3) (Total 6 marks) Q32. (a) A person takes their dog for a walk. The graph shows how the distance from their home changes with time. Which part of the graph, A, B, C or D, shows them walking the fastest? Write your answer in the box. Give the reason for your answer. ........................................................................................................................ ........................................................................................................................ (2) (b) During the walk, both the speed and the velocity of the person and the dog change. How is velocity different from speed? ........................................................................................................................ ........................................................................................................................ (1) (Total 3 marks) Q33. (a) A car is being driven along a straight road. The diagrams, A, B and C, show the horizontal forces acting on the moving car at three different points along the road. Describe the motion of the car at each of the points, A, B and C. (3) (b) The diagram below shows the stopping distance for a family car, in good condition, driven at 22 m/s on a dry road. The stopping distance has two parts. (i) Complete the diagram below by adding an appropriate label to the second part of the stopping distance. ............................................................. ............................................................. (1) (ii) State one factor that changes both the first part and the second part of the stopping distance. ............................................................................................................... (1) (c) The front crumple zone of a car is tested at a road traffic laboratory. This is done by using a remote control device to drive the car into a strong barrier. Electronic sensors are attached to the dummy inside the car. (i) At the point of collision, the car exerts a force of 5000 N on the barrier. State the size and direction of the force exerted by the barrier on the car. ............................................................................................................... ............................................................................................................... (1) (ii) Suggest why the dummy is fitted with electronic sensors. ............................................................................................................... ............................................................................................................... (1) (iii) The graph shows how the velocity of the car changes during the test. Use the graph to calculate the acceleration of the car just before the collision with the barrier. Show clearly how you work out your answer, including how you use the graph, and give the unit. ............................................................................................................... ............................................................................................................... ............................................................................................................... ............................................................................................................... Acceleration = ............................................................ (3) (Total 10 marks) Q34.The diagram, which is not to scale, shows two satellites, L and M, orbiting the Earth. (a) Complete the following table. Each letter, L or M, may be used once, more than once, or not at all. Statement about the satellite Letter for the satellite It is used as a monitoring satellite. It is a geostationary satellite. It takes 24 hours to complete its orbit. (2) (b) Complete the following sentence. To stay in its present orbit around the Earth, each satellite must move at a particular .................................................. . (1) (c) Thousands of satellites are now in orbit around the Earth. A student used the internet to collect information about some of them. Name of satellite Average distance from the centre of the Earth in kilometres Speed in kilometres per second Time taken to orbit the Earth The Moon 391 400 1.01 28 days (i) GEO 42 200 3.07 1 day Navstar 26 600 3.87 12 hours Lageos 12 300 5.70 3.8 hours HST 7 000 7.56 97 mins ISS 6 700 7.68 92 mins The Moon takes a longer time than any of the other satellites to orbit the Earth. Give one other way in which the Moon is different from the other satellites in the table. ............................................................................................................... ............................................................................................................... (1) (ii) What conclusion on the relationship between the average distance and speed can the student come to on the basis of this data? ............................................................................................................... ............................................................................................................... (1) (Total 5 marks) Q35.The diagram, which is not to scale, shows two satellites, L and M, orbiting the Earth. (a) Complete the following table. Each letter, L or M, may be used once, more than once, or not at all. Statement about the satellite Letter for the satellite It is used as a monitoring satellite. It is a geostationary satellite. It takes 24 hours to complete its orbit. (2) (b) Complete the following sentence. To stay in its present orbit around the Earth, each satellite must move at a particular .................................................. . (1) (c) Thousands of satellites are now in orbit around the Earth. A student used the internet to collect information about some of them. (i) Name of satellite Average distance from the centre of the Earth in kilometres Speed in kilometres per second Time taken to orbit the Earth The Moon 391 400 1.01 28 days GEO 42 200 3.07 1 day Navstar 26 600 3.87 12 hours Lageos 12 300 5.70 3.8 hours HST 7 000 7.56 97 mins ISS 6 700 7.68 92 mins The Moon takes a longer time than any of the other satellites to orbit the Earth. Give one other way in which the Moon is different from the other satellites in the table. ............................................................................................................... ............................................................................................................... (1) (ii) What conclusion on the relationship between the average distance and speed can the student come to on the basis of this data? ............................................................................................................... ............................................................................................................... (1) (Total 5 marks) M1. (a) (i) decreases for 1 mark 1 (ii) decreases for 1 mark 1 (iii) lower speed everywhere for 1 mark 1 (b) (i) 3a= or a = gains 1 mark 1 ms–2 gains 1 mark 1 (ii) 2850 ecf gains 2 marks else working gains 1 mark 2 (iii) air resistance/frictional forces increase with speed; till frictional force = max forward engine force; when acceleration is zero (incorrect statement – 1 mark) or (limitation on maximum speed for safety-1 mark) any two for 1 mark each 2 [9] M2. (a) 3 gains 1 mark m/s2 gains 1 mark else working gains 1 mark 2 (b) 2850 ecf gains 1 mark N gains 1 mark else working gains 1 mark 2 (c) friction/air resistance increases with speed;till frictional = max forward force;then force/acceleration is zero for 1 mark each alternative limitation for safety gains 1 mark only 3 [7] M3. (i) force = mass acceleration accept F = m a accept upper or lower case letters accept equation using correct units accept if subsequent method correct 1 (ii) 0.007 allow 1 mark for correct transformation or substitution 2 [3] M4. (a) (i) same size 1 (ii) K 1 (b) velocity 1 (c) C 1 greatest mass or because it’s heavier accept biggest load accept heaviest or more weight do not accept fuller do not accept more items do not accept it’s loaded do not accept loaded most ignore references to time as neutral 1 [5] M5. (a) (i) linear scales used do not credit if less than half paper used 1 points plotted correctly all of paper used 1 (straight) line of best fit drawn allow a tolerance of half square 1 (ii) correct and straight line through origin all needed e.c.f. if their (a)(i) is straight but not through the origin - incorrect because line does not go through origin credit a calculation that shows proportionality 1 (iii) 62 ± 0.5 (m) credit 1 mark for KE = 490000 or 490kJ credit 1 mark for correct use of graph clearly shown 2 (iv) any one from: wet or icy or worn or smooth road accept slippery slope brakes worn accept faulty brakes car heavily loadedworn tyresdownhill slope do not accept anything to do with thinking distance e.g. driver tired or drunk 1 (b) (i) acceleration = accept correct transformation accept accept m/s2 = do not accept acceleration = 1 (ii) 56 accept –56 1 (iii) deceleration is reduced accept deceleration is slower accept acceleration 1 force on car and or passengers is reduced accept an answer in terms of change in momentum for full credit 1 [11] M6. (i) C and D or D and C accept CD accept DC accept answers in terms of time 1 (ii) any one from: streamline position streamline clothes accept crouched positionaccept tight clothesaccept design of cycleaccept cycle slower 1 (iii) 0.5 hours or 30 minutes or 1800 seconds must have unit 1 (iv) speed = accept any correct rearrangement accept s = d/t or v s/t accept velocity for speed accept if subsequent use of correct 1 (v) 16 allow for mark for each of time = 3.5 hours distance = 56km allow e.c.f. from part (a)(iii) if correctly used an answer of 14 gains 2 marks allow 1 mark for correct attempt to average the three sections 3 [7] M7. (i) first statement must be accelerated if it just accelerated then decelerates award 2 marks 1 final statement must be stationary 1 interim statement decelerates 1 (ii) direction is changing 1 [4] M8. (a) (i) gravity/weight 1 (ii) 2193750000000 or 2.19 × 1012 not 2.1912 allow 1 mark for the correct conversion to 7500 (m/s) allow one mark for answer 2193750(J) 2 transferred to heat ignore extras of sound and light accept changed to heat accept lost due to friction 1 (b) (i) acceleration = accept word speed instead of velocity accept a = or correct rearrangement do not accept even if subsequent calculation correct can gain credit if subsequent calculation correct 1 (ii) 2 ignore + or – signs m/s2 1 accept m/s/s or ms2 2 (c) (i) force = mass × acceleration accept correct rearrangement accept F = m × a do not accept unless subsequent calculation correct 1 (ii) 156 000 accept 78 000 × their (b)(ii)(only if (b)(i) correct) 1 [9] M9. (a) (i) constant speed do not accept normal speed do not accept it is stopped / stationary 1 in a straight line accept any appropriate reference to a direction constant velocity gains 2 marks ‘not accelerating’ gains 2 marks terminal velocity alone gets 1 mark 1 (ii) goes down owtte accept motorbike (it) slows down 1 (b) (i) 20 (m/s) ignore incorrect units 1 (ii) acceleration = do not accept velocity for change in velocityaccept change in speed accept or or a = do not accept 1 (iii) 4 or their (b)(i) ÷ 5 allow 1 mark for correct substitution 2 m/s2 m/s/s or ms or metres per second squared or metres per second per second 1 (c) vehicle may skid / slide loss of control / brakes lock / wheels lock accept greater stopping distance or difficult to stop 1 due to reduced friction (between tyre(s) and road) accept due to less grip do not accept no friction 1 (d) any three from: do not accept night time / poor vision • increased speed • reduced braking force • slower (driver) reactions NB specific answers may each gain credit eg tiredness (1), drinking alcohol (1), using drugs (1), driver distracted (1) etc • poor vehicle maintenance specific examples may each gain credit eg worn brakes or worn tyres etc • increased mass / weight of vehicle accept large mass / weight of vehicle • poor road surface • more streamlined if candidates give three answers that affect stopping distance but not specific to increase award 1 mark only 3 [13] M10. (a) Quality of written communication for correct use of term speed in all correct examples Q Q 1 describes all 3 sections correctly for 2 marks describes 2 or 1 section correctly for 1 mark max 2 A – B constant speed do not accept pace for speed B – C (has accelerated) to a higher (constant) speed C – D goes back to original / lower (constant) speed allow for 1 mark, initial and final (constant) speeds are the same accept velocity for speed ignore reference to direction (b) 62.5 allow answer to 2 s.f. allow 1 mark for drawing a correct triangle or for using two correct pairs of coordinates allow 1 mark for correct use of y/x ignore units 3 [6] M11. (a) (i) accelerating accept getting faster accept speed / velocity increasing 1 (ii) acceleration increases accept velocity / speed increases more rapidly do not accept velocity / speed increases 1 (b) (i) acceleration = accept a = or a = do not accept velocity for change in velocity do not accept change in speed do not accept a = 1 (ii) 15 allow 1 mark for an answer of 900 or for correct use of 540 seconds 2 (iii) velocity includes direction accept velocity is a vector (quantity) accept converse answer 1 [6] M12. (a) 60 1 (b) 5 hours must include unit 1 (c) 30 1 (d) 30 minutes or hour must include unit 1 (e) D and E accept finish for E accept correct numbers from axes with units 1 least steep part of the graph accept covers smallest distance in a set time accept only moves 5 km in 1 ½ hours (accept anything between 5 and 6) ignore horse is tired 1 [6] M13. (a) concentration / tiredness / drugs / alcohol accept any reasonable factor that could affect a driver’s reactions do not accept speed or any physical condition unrelated to the driver 1 (b) 31.25 credit for 1 mark correct attempt to calculate the area under the slope or for using the equation distance = average velocity (speed) × time credit for 1 mark use of correct velocity change (12.5) and correct time (5) or answer of 62.5 3 (c) 2.5 credit for 1 mark triangle drawn on slope or correct equation ortwo correct pairs of coordinates credit for 1 mark use of correct velocity change (12.5) and correct time (5)accept time = between 4.8 and 5.2 if used in (b) do not accept an attempt using one pair of coordinates taken from the slope 3 metres / second / second or metres / second / squared or m/s2 or ms–2 1 (d) (i) force = mass × acceleration accept correct transformation accept F = m × a accept provided subsequent use of Δ is correct do not accept an equation in units 1 (ii) 2250 credit their (c) × 900 for 2 marks credit 1 mark for correct substitution 2 [11] M14. (a) MN accept 5.8, 8 seconds must include unit 1 (b) LM accept 0.8, 5.8 seconds must include unit 1 (c) (i) 0.8 1 (ii) drinking alcohol 1 (d) straight (by eye) line starting at 0.8 seconds 1 line drawn steeper than LM starting before L ignore lines going beyond 2 seconds but line must exceed 2.5 metres per second before terminating 1 [6] M15. (a) 4 allow 1 mark for extracting correct information 12 2 m/s2 ignore negative sign 1 (b) 9 (s) 1 [4] M16. (a) (i) 0.6 allow 1 mark for correct substitution 2 newtons accept N do not accept n accept Newtons 1 (ii) the same as 1 (b) (i) changed velocity accept increased/ decreased for change accept speed for velocity accept change direction accept getting faster/ slower accept start/ stop moving accept correct equation in terms of change in speed or change in velocity 1 (ii) down(wards) accept towards the ground accept ↓ do not accept south 1 (iii) increase velocity is increasing can only credit second mark if answer is increase or it is accelerating accept speed for velocity accept is moving faster 1 accept an answer in terms of resultant force downwards mention of weight/ mass increasing negates second mark 1 [8] M17. (a) (i) velocity includes direction accept velocity is a vector 1 (ii) 64 allow 1 mark for obtaining values of 16 and 4 from the graph or marking correct area or correct attempt to calculate an area 2 (iii) any two from: • velocity zero from 0 to 4 seconds • increasing in 0.2 s (or very rapidly) to 8 m/s • decreasing to zero over the next 8 seconds 2 (iv) momentum before does not equal momentum after ignore reference to energy or total momentum changes or an external force was applied 1 (b) to reduce the momentum of the driver 1 a smaller (constant) force would be needed do not accept reduces the impact / impulse on the driver 1 [8] M18. (a) shallowest slope/ gradient accept smallest distance in biggest time accept longest time to travel the same distance accept the line is not as steep accept it is a less steep line do not accept the line is not steep 1 (b) A–B If 2 or 3 boxes are ticked no mark 1 (c) (i) 200 m 1 (ii) 20 s allow 1 mark for correctly identifying 60 s or 40 s from the graph 2 (d) (i) straight line starting at origin accept within one small square of the origin 1 passing through t = 200 and d = 500 1 (ii) 166 accept any value between 162 and 168 accept where their line intersects given graph line correctly read ± 3 s 1 [8] M19. (a) (i) 4.5 allow 1 mark for correct substitution i.e. 9 ÷ 2 2 (ii) m/s2 accept answer given in (a)(i) if not contradicted here 1 (iii) speed 1 (iv) straight line from the origin passing through (2s, 9m/s) allow 1 mark for straight line from the origin passing through to t = 2 seconds allow 1 mark for an attempt to draw a straight line from the origin passing through (2,9) allow 1 mark for a minimum of 3 points plotted with no line provided if joined up would give correct answer. Points must include(0,0) and (2,9) 2 (b) (i) B if A or C given scores 0 marks in total 1 smallest (impact) force 1 on all/ every/ any surfaces these marks are awarded for comparative answers 1 (ii) (conditions) can be repeated or difficult to measure forces with human athletes accept answers in terms of variations in human athletes e.g. athletes may have different weights area / size of feet may be different difficult to measure forces athletes run at different speeds accept any answer that states or implies that with humans the conditions needed to repeat tests may not be constant e.g. athletes unable to maintain constant speed during tests (or during repeat tests) do not accept the robots are more accurate removes human error is insufficient fair test is insufficient 1 [10] M20.(a) (i) B and C both required and no other 1 same speed and direction 1 (ii) Vector Scalar (force) distance acceleration kinetic energy momentum time weight 1 mark for each correct answer 6 max (b) (i) the front of the trolley is not level with the end of the metre rule 1 the stop clock has not been reset to zero 1 (ii) as the force increases so does the average speed accept reference to positive correlation accept numerical example 1 the increase in speed is not linear / not directly proportional 1 (c) (i) a single force that has the same accept all the forces added 1 effect as all the forces combined or the sum of the forces or overall force (ii) constant velocity or constant speed (in a straight line) 1 (d) 1 1200 correct answer with or without working gains 2 marks 1 (e) both cars are travelling at the same initial velocity accept converse throughout 1 car B starts decelerating (0.8 seconds) after car A 1 the thinking time for driver B is longer 1 both cars decelerate at the same rate 1 car B stops (0.8 seconds) after car A 1 and travels (12 metres) further 1 (f) Z 1 it gives a unique value of resistance for each force applied accept different force values give a different resistance value accept answers in terms of why X and Y would not be best, eg X – same resistance value is obtained for 2 different force values and Y – all force values give the same resistance 1 there is a linear relationship between resistance and force do not accept force and resistance are (directly) proportional 1 [25] M21.(a) equal to or the same as 1 (b) momentum of car before collision = 1200 × 10 = 12 000 1 momentum after collision = 12 000 1 or momentum is conserved equating ie 12 000 = 1200 × 2 + 3200v 1 3 (m/s) correct answer with or without working gains 4 marks 1 (c) correct area used from the graph 1 1.5 (m) correct answer with or without working gains 2 marks 1 (d) the time taken for the driver to stop (moving forward) increases 1 which decreases the rate of change in momentum accept reduces deceleration 1 so the force on the driver is reduced 1 [10] M22. (a) 35 (m) allow 1 mark for indicating the correct area allow 1 mark for obtaining correct figures from the graph allow 1 mark for calculating area of triangle (25) but omitting the rectangle underneath (2 x 5) 3 (b) 86 400 allow 1 mark for correct substitution into the correct equation ie 1/2 × 1200 × 122 2 [5] M23. (a) 1.25 allow 1 mark for correct resultant force ie 1500N allow 2 marks for correct transformation and substitution ie allow 1 mark for a correct transformation but clearly substituting an incorrect value for force eg = 3 m/s2 1 (b) as speed increases so does the size of the drag force accept frictional force / resistive force / air resistance for drag 1 eventually the drag force becomes equal to the thrust 1 the resultant force is now equal to zero and therefore there is no further acceleration 1 (c) the car and van will reach top speed when the forward force equals the drag force accept air resistance / frictional / resistive force for drag force 1 the drag force at any speed is smaller for the car than for the van 1 as the car is more streamlined 1 therefore the car’s drag force will equal the forward force at a higher speed 1 allow converse throughout [11] M24. 1 mark for each line if more than 1 line is drawn from a graph in List A then all those lines are marked incorrect [3] M25. (a) 96 allow 1 mark for correct substitution ie 80 × 1.2 2 newton or N allow Newton do not allow n 1 (b) (i) direction 1 (ii) velocity and time are continuous (variables) answers must refer to both variables accept the variables are continuous / not categoric accept the data / ‘it’ is continuous accept the data / ‘it’ is not categoric 1 (iii) C 1 velocity is not changing the 2 marks for reason may be scored even if A or B are chosen accept speed for velocity accept speed is constant (9 m/s) accept not decelerating accept not accelerating accept reached terminal velocity 1 forces must be balanced accept forces are equal accept arrows are the same length / size or resultant force is zero do not accept the arrows are equal 1 [8] M26. (a) 4.2 2 marks for correct substitution and transformation, ie 1155/275 allow 1 mark for correct resultant force with a subsequent incorrect method, ie 1155 allow 1 mark for an incorrect resultant force with a subsequent correct method, eg answers of 7.27 or 10.34 gain 1 mark 3 (b) (i) YES marks are for the explanation any two from: • data (from police files) can be trusted • data answers the question asked allow a conclusion can be made from the data • large sample used NO any two from: • the sample is not representative • the sample size is too small • accident files do not indicate age / experience of riders an answer YES and NO can score 1 mark from each set of mark points 2 (ii) more accidents with motorbikes up to 125 cc accept for 2 marks an answer in terms of number of under 125 cc to accidents ratio compared correctly with number of over 500 cc to accidents ratio 1 even though there are fewer of these bikes than bikes over 500 cc 1 (c) (i) increases the time taken to stop accept increases collision time 1 decreases rate of change in momentum accept reduces acceleration / deceleration accept reduces momentum is insufficient 1 reduces the force (on the rider) 1 (ii) YES any sensible reason, eg: the mark is for the reason • cannot put a price on life / injury accept may save lives • fewer (serious) injuries accept reduces risk of injury • reduces cost of health care / compensation NO any sensible suggestion, eg: • money better spent on … needs to be specific • total number of riders involved is small 1 [11] M27. (a) 48 allow for 1 mark correct method shown, ie 6 × 8 or correct area indicated on the graph 2 (b) diagonal line from (0,0) to (6,48) / (6, their (a)) if answer to (a) is greater than 50, scale must be changed to gain this mark 1 horizontal line at 48m between 6 and 10 seconds accept horizontal line drawn at their (a) between 6 and 10 seconds 1 [4] M28. (a) (i) lorry reason only scores if lorry chosen 1 greatest mass accept weight for mass accept heaviest accept correct calculations for all 3 vehicles the biggest is insufficient 1 (ii) 2450 allow 1 mark for correct substitution ie 175 × 14 2 (b) (i) increases accept any clear indication of the correct answer 1 (ii) speed increases accept velocity for speed accept gets faster do not accept it accelerates on its own moves more is insufficient 1 (iii) straight line going to 6, 20 allow 1 mark for a curve going to 6,20 or a straight line diagonally upwards but missing 6,20 2 horizontal line from 6,20 to 8,20 allow a horizontal line from where their diagonal meets 20m/s to 8,20 1 [9] M29.(a) (i) 120 1 (ii) 20 accept 140–their (a)(i) provided answer is not negative 1 (iii) as speed increases 1 drag force / water resistance / friction / D increases 1 (until) D = 140 N or (until) D = T forces balance is insufficient 1 (b) (i) (average) speed (of swimmer) 1 (ii) any two from: • more data accept results for data do not accept more accurate data • force may vary (a lot) / change • give more reliable average ignore references to anomalies ignore accurate / precise 2 (iii) examples of acceptable responses: • most / some females produce smaller forces do not accept all females produce smaller forces • most / some males produce larger forces do not accept all males produce larger forces • some females swim as fast as males but use a smaller force • most of the faster swimmers are male do not accept all males swim faster • most of the slower swimmers are female do not accept all females swim slower • range of the (average) speed of males is smaller than the range of the (average) speed of females • range of the (average) force of the males is greater than the range of the (average) force of the females 1 (iv) exert maximum (hand) force (throughout the swim / stroke) accept (any method to) increase (hand) force practise more is insufficient 1 [10] M30. (a) (i) 12 1 (ii) 0.2 allow 1 mark for their (a)(i) ÷ 60 and correctly calculated 1 m/s2 accept correct unit circled in list accept ms−2 do not accept mps2 1 (b) B 1 [4] M31. (a) 2.75 allow 1 mark for correct substitution, ie or provided no subsequent step shown 2 m/s2 1 (b) driving force increases 1 frictional force increases accept air resistance / drag for frictional force 1 driving force > frictional force 1 [6] M32. (a) B reason only scores if B is chosen 1 gradient / slope is the steepest / steeper answers must be comparative accept steepest line ignore greatest speed 1 (b) (velocity includes) direction ‘it’ refers to velocity 1 [3] M33. (a) A constant speed / velocity accept steady pace do not accept terminal velocity do not accept stationary 1 B acceleration accept speeding up 1 C deceleration accept slowing down accept accelerating backwards accept accelerating in reverse do not accept decelerating backwards 1 (b) (i) the distance the car travels under the braking force accept braking distance 1 (ii) speed/velocity/momentum 1 (c) (i) 5000 (N) to the left both required accept 5000(N) with the direction indicated by an arrow drawn pointing to the left accept 5000(N) in the opposite direction to the force of the car (on the barrier) accept 5000(N) towards the car 1 (ii) to measure/detect forces exerted (on dummy / driver during the collision) 1 (iii) 4 allow 1 mark for showing a triangle drawn on the straight part of the graph or correct use of two pairs of coordinates 2 m/s2 do not accept mps2 1 [10] M34.(a) all correct M L L allow 1 mark for one correct 2 (b) speed accept ‘velocity’ 1 (c) (i) any one from: • it’s natural • slowest • furthest (from the centre of the Earth) accept ‘others are artificial / made by humans’ 1 (ii) as the (average) distance decreases the speed increases accept ‘there is a negative correlation (between them)’ do not accept ‘they are inversely proportional’ 1 [5] M35.(a) all correct M L L allow 1 mark for one correct 2 (b) speed accept ‘velocity’ 1 (c) (i) any one from: • it’s natural • slowest • furthest (from the centre of the Earth) accept ‘others are artificial / made by humans’ 1 (ii) as the (average) distance decreases the speed increases accept ‘there is a negative correlation (between them)’ do not accept ‘they are inversely proportional’ 1 [5] E1. Part (a) was a good start to the question with the vast majority of candidates scoring marks. In part (b) many candidates did the two calculations correctly and then ran into trouble with explaining the top speed of a car. Candidates did not appear to be familiar with the syllabus statements on this topic. E2. Parts (a) and (b) were quite well answered, the main loss of marks being due to unit errors or omissions. Part (c) was not well answered and there was little evidence of candidates being familiar with the syllabus statements on this topic. E3. This question was well answered with candidates often scoring full marks. However in part (ii) some candidates thought that to calculate deceleration they needed to invert the equation for acceleration. E4. In part (a) many candidates were unaware that an object can continue at a constant speed if opposing forces are balanced, and that a straight line graph of proportionality would result. In part (b) only a minority of candidates knew the definition of acceleration. In part (c), most candidates identified trolley C as having the smallest acceleration but many candidates did not correctly link the greater mass as being the cause for the smallest acceleration. Candidates need reminding that imprecise answers such as ‘because it’s got more stuff in it’ are not acceptable. E5. The graph in part (a)(i) was well approached. Most candidates chose sensible scales, and there were only occasional errors in plotting. There were still a significant number of dot-to-dot lines drawn. Answers to part (a)(ii) were often imprecise, a common reason being ‘strong correlation’ and other statements sounding pertinent. Reference to the line being straight and through the origin were less frequent. In part (a)(iii) many candidates calculated 490 Id correctly, and many went on to use this information to obtain the braking distance. Some candidates failed to show how they had obtained their answer and so were unable to score credit if the answer was outside tolerance. Part (a)(iv) was generally correct but there were two types of answer which did not score. Firstly there were many answers like ‘mass’ or ‘friction’ which did not speci1_ whether it was greater or smaller to increase the braking distance. Secondly there were answers relating to the driver, commonly with reference to alcohol or drugs. Parts (b)(i) and (b)(ii) were generally correct. In part (b)(iii) the better candidates often made a comment about smaller deceleration but then failed to relate this to a reduced force on the car or passengers. Some candidates tried to explain how the crumple zone absorbs the energy but rarely in a credit worthy manner. E6. Foundation Tier This question was generally well answered with appropriate information being extracted from the graph and a correct equation provided. However, many candidates lost marks by using the total journey time in their calculation, having forgotten that the cyclist had stopped and rested. Higher Tier Candidates generally scored highly on this question. It was usually well answered with appropriate information being extracted from the graph and a correct equation provided. However, some candidates lost marks by using the total journey time in their calculation, having forgotten that the cyclist had stopped and rested. E7. Part (i) was generally well done, the deceleration being the step most frequently missed out. A few candidates seemed to confuse the graph with a speed-time graph and stated that the horizontal line indicated a constant speed. E8. This question was well answered. However, it was disappointing that a substantial minority of candidates could not recall the equations correctly or complete a calculation without error even when they had written the equation. A common error in part (a)(ii) was to leave the speed in km/s rather than converting to mis. Most candidates had the right idea in part (a)(iii), but not all were specific enough to gain credit. In part (b)(ii) many candidates were able to work out the deceleration For those that did not, a common error was to use the orbital speed in the calculation. A number of candidates either omitted, or did not know, the correct unit for acceleration. In part (c)(ii) most candidates who had previously calculated the correct deceleration went on to calculate the correct force. A number of candidates failed to make the link between parts (b) and (c) and in the absence of any stated value for acceleration chose to use 10 m/s2. E9. Although in part (a) the stem of the question clearly stated that the motorbike was moving, and the artwork reinforced this image of movement, many candidates incorrectly stated that the motorbike would be stationary. This was often followed by a statement that the motorbike would go backwards. In part (b) few candidates were able to recall the equation for acceleration or the correct unit. There were very few correct calculations. In part (c) most candidates were able to describe and explain what would happen to a car braking on an icy road and also give factors that could cause stopping distance to increase. However a number of candidates used imprecise language which meant that answers could not gain credit. E10. (a) The poor use of English seemed to hinder many candidates. A significant number had difficulty expressing that speed had changed at a point rather than between points. However, the vast majority of candidates did seem to realise that the speed was constant between each pair of points. There were a few who thought the car was accelerating throughout. (b) E11. The calculation of gradient was correctly completed by a good range of candidates. However, it was common to see 5/4 rather than the actual coordinates. Foundation Tier This question was poorly answered. (a) Most candidates were unable to relate the information given to the motion of the shuttle. (b) Although the equation was correctly recalled by some candidates, most went on to calculate an answer using time in minutes. In part (b)(iii) the difference between speed and velocity was not widely known. The misconception that there is ‘no gravity outside the atmosphere’ so the space shuttle ‘floated’ in orbit prevented many candidates from being given any credit. Higher Tier (a) Most candidates were unable to relate the information given to the motion of the shuttle. There were few references to speed or acceleration. (b) Although the equation was correctly recalled by many candidates, most went on to calculate an answer using time in minutes. In part (b)(iii) the difference between speed and velocity was generally known, although some candidates were compromised by their lack of linguistic skills, giving answers such as ‘velocity is a direction’. The misconception that there is ‘no gravity outside the atmosphere’ prevailed in many answers, and a significant minority referred to the gravitational pull of the Sun. Very few candidates correctly talked about the role of the orbital speed of the shuttle. E12. All parts of this question were well answered. Many candidates expressed their answer in terms of the state of the tired horse. E13. E14. E15. (a) Most candidates were able to gain the mark with alcohol/drugs or distractions. Those who failed to do so usually referred to weather/road conditions. (b) Candidates who read the graph correctly, and knew how to use the information obtained, were able to score maximum marks. Errors included misreading the time (5.2 or 6) or the final velocity (15). Of those candidates who used the equation, few gave distance = ‘average’ velocity (speed) × time. (c) Most candidates scored maximum marks using 12.5/5 = 2.5, but not always showing clearly ‘increase in velocity/time taken’. The majority of candidates gained the unit mark. (d) Most candidates were able to gain full marks provided that they had an answer in part (c). Candidates were generally happy to use the letters in bold on the graph to identify different stages in the car’s journey. Where candidates supplied graph co-ordinates, many produced numerical values without stating the axis used. (c) Most candidates achieved a least partial success. (d) Many candidates did not offer responses to this part of the question. Those that did showed a widespread lack of understanding that the angle of slope of the line that they drew should be directly related to the greater initial acceleration of the cyclist. This was well done by candidates, a significant number gaining full marks. However, many candidates were not confident of the unit. If the calculation was incorrect the unit mark was rarely scored. The majority of candidates scored this mark. The most common incorrect answer being 6 seconds. E16. (a) (b) E17. (b) (i) Most candidates were able to use the data and equation provided to produce a numerical value for the weight of the toy but there were few responses which stated the correct unit. (ii) Most of the candidates were aware that the forces involved would need to be balanced to enable the toy to hover. (i) Most candidates were able to explain the term ‘acceleration’ however, there were many references to ‘move’, ‘increase’ etc without any elaboration. (ii) This was question was generally answered correctly however, there were a number of incorrect references to ‘south’. (iii) Half of the candidates understood that the momentum would increase but few could give a valid reason why. (a) (i) Most candidates stated that velocity is speed in a given direction. Few candidates stated that velocity is either speed in a straight line or velocity = speed × time. (ii) A good proportion of candidates obtained 64 metres but many candidates correctly obtained 16 and 4 from the graph and then divided the two numbers. Some candidates did a longer calculation and obtained the complete area under the graph. (iii) This question was well done with the majority of candidates scoring both marks. However some candidates either misread the question and redrew graph 1 or were at least one small square out in their accuracy. (iv) Many candidates were able to score a mark however the majority simply quoted the law of conservation of momentum. Many candidates did not score any marks here and wrote about whiplash and trying to avoid serious injuries. Some realised that if the force was to be constant over the same time period then it must be smaller. Some candidates were familiar with the equation linking force and rate of change of momentum but were unable to link this with any logical explanation. E18. (a) More than half of the candidates did not score this mark. The most usual reason was that the answer gave no comparison with the other parts of the journey. ‘The line has a small gradient’ or ‘the bus took a long time to travel 150m’ were common answers that gained no credit. (b) Although over half of the candidates scored this mark many candidates failed to gain credit by ticking two of the available boxes. (c) (i) Nearly all candidates were able to read the distance correctly from the graph. (ii) Again most candidates were able to extract the correct information from the graph. (i) Most candidates drew a straight line from the origin, but many candidates did not recognise that the distance would still be 500m and so did not draw the line through (200, 500). (ii) The failure of many candidates to choose the correct co-ordinates for the termination of the cyclist’s journey meant that less than half of the candidates found the point where the cyclist overtook the bus and thus identified the time at which this event occurred. (d) E19. Foundation Tier (a) (b) (i) This was well answered with most candidates gaining both marks. (ii) It is surprising that only just over 50 % of the candidates knew the unit of acceleration. (iii) For a standard piece of recall it was surprising that only 50 % of candidates scored a mark. (iv) Less than 50 % of candidates drew the correct line and gained 2 marks. Many candidates did not take into account the final velocity of 9 m/s. Others did not relate the idea of constant acceleration to a straight line. (i) Candidates that chose the correct shoe of the three on test often gave a suitable reason for their choice to achieve 2 marks, but then failed to appreciate that this shoe was the best on all of the listed types of surface. However nearly 50% of candidates were unable to interpret the bar chart correctly and chose either A or C. (ii) Most correct answers were in terms of human variability but many candidates mentioned the robot’s consistency. A significant number of candidates did not recognize the importance of the word ‘reliable’ and answered in terms of sensor accuracy. Higher Tier (a) (b) E25. (i) Most candidates obtained the correct answer although a few candidates multiplied 9 × 2 instead of dividing. (ii) The majority of candidates knew that the unit of acceleration was m/s2. (iii) The majority of candidates gave the correct answer. (iv) Most candidates produced a straight line with a ruler from the origin to (2,9). Those who did not obtain full marks were generally not accurate enough. A number of candidates did not link the idea of constant acceleration with the need to draw a straight line. (i) Many candidates correctly chose B but then failed to compare this shoe with both A and C or mention that it was the best shoe on all three surfaces. However a significant number of candidates did score all three marks. (ii) The majority of candidates obtained the mark, usually giving answers in terms of variations in human athletes eg weight / size of foot may be different and they run at different speeds. A common fault was to be too vague and say that the robots are more accurate or they remove human error; a few answered with the standard response ‘it’s a fair test’ without qualifying the statement. (a) Many candidates were able to perform the calculation correctly but few candidates were able to supply the correct unit. There were many instances where the candidates substituted 1.2 m/s 2 into the equation and then went on to either use 1.22 or 1.2 × 2 in their calculation. (b) (i) It was disappointing that very few candidates gave the correct answer to this question, the majority of the incorrect answers being mass, acceleration, momentum and time. (ii) Again there were very few correct answers. Most candidates thought that the use of a line graph was to improve the presentational appearance of the data and to make the data easier to understand. (iii) Most candidates scored at least 2 marks, generally for choosing C and then stating that the forces were equal or the arrows were the same length. A significant minority of candidates chose B because the resultant force forwards would be the greatest so the cyclist would be going the fastest ie, 9 m/s. E26. (a) Many candidates obtained the correct answer having correctly calculated the resultant force as 1155 N. Correct calculation of the force 1155 N then multiplying by the mass of 275 kg was a common error gaining just one mark. The use of an incorrect force with the correct method, gained many candidates one compensatory mark. (b) (c) E27. (i) Many candidates failed to understand that the question was referring to the validity of the data with many answers given in the form of a conclusion rather than answering the question about valid data. Those candidates who realised the question was about the data, answered mainly in terms of the reliability of police files (YES) or on the lack of information about ages (NO). Many candidates quoted the number of files in the source, but as they failed to express whether this was a large or a small sample, failed to score a mark for this. There was also evidence of much rewriting of answers, mostly to little or no advantage. (ii) Just over half of candidates gained one mark for describing how the smaller motorbikes had more accidents and a small minority of candidates went on to note how there were fewer smaller bikes than larger bikes, or calculated ratios. (i) Very few candidates gained full marks on this question, in spite of it being a well examined aspect of the course. A change in context does disguise what is needed to all but the highest scoring candidates, in spite of the stem referring to momentum. Over half of candidates scored zero. The quality of the explanation was often poor. There are still a large number of answers referring to cushioning the impact rather than reducing the force. The‘decreases rate of change of momentum’ is the most frequently missed mark. A number of candidates confused their response with references to kinetic energy and stopping distances. (ii) Most candidates gave the answer that the new safety barriers would save lives, or reduce injuries, which gained the mark. Those who thought that 17m/s was too slow to crash or cause serious injury had confused the unit with mph.‘Money could be better spent’ was rarely a complete answer and so did not score a mark very often. (a) Nearly three quarters of candidates calculated the correct answer and scored both marks. The most common incorrect answers were where candidates had used distance = speed × time with incorrect figures, usually 8 × 10, or had arrived at an answer by dividing numbers, eg 8/6 or 10/8, showing failure to understand graphical representation of motion, including the idea of distance travelled being area under graph. (b) Even those candidates who scored two marks in part (a) often lost marks here, with only two fifths of candidates gaining both marks. There were many incorrect permutations of graphs - some repeated the graph from part (a) either at the same or different values, some had a diagonal line up and then down, many had a correct shape but at incorrect values of time and distance (45 was a common wrong value) or just a diagonal line to t = 10 s. Just over a further tenth of candidates scored one mark, usually for the first half of the graph. Very few candidates failed to attempt this part question. E28. (a) (ii) (b) (a) (b) This part question was generally answered well by those candidates with access to calculators. Candidates should be encouraged to check their calculations carefully as there were a number of instances of errors occurring in the transfer of the numbers from the question stem to the lines provided, to show their method of calculating the momentum of the motorbike. (i)&(ii)Just over nine tenths of candidates correctly answered that the kinetic energy would increase but they had less success in giving an appropriate reason. Most of the incorrect responses were in terms of the motorbike accelerating which had been stated in the part question stem. There were also many vague responses involving changes of force, power, friction, engine efficiency, etc. (iii) E29. (i) Most candidates were aware that the lorry would have the greatest momentum by reason of its greater mass. Vague responses, such as‘the lorry is bigger’, did not gain a mark. Some candidates took advantage of the relevant equation printed on the same page and calculated the momentum of the three vehicles. Incorrect responses generally involved the motorbike and indicated that the candidates were confusing momentum with the ability of the motorbike to accelerate faster than the other two. Just over three quarters of candidates gained all three marks. Those that did not often drew a diagonal line from (4, 14) up to 20 m/s on the y-axis but the lines did not hit (6, 20) and were not subsequently continued horizontally to 8 s on the x-axis. (i) Most candidates recognised that the constant speed of the swimmer was due to the forces being equal. (ii) This part question was not answered well. A simple subtraction of the two forces would produce the correct resultant force but unfortunately, many candidates opted to add, multiply or divide the values of the two forces or simply copy the value of one of the forces. (iii) The majority of candidates either scored zero on this part question or opted to leave it blank. The majority of the incorrect responses involved a decrease in the amount of drag, leading to the swimmer becoming stationary. There were also many answers involving upthrust, gravity, currents in the water and suggestions that the swimmer may, by altering his swimming technique, reduce the resultant force to zero. (i) It was surprising that only one-fifth of candidates were able to identify the dependent variable from information in the stem of the question and from the axes of the graph, the most common error being to state the gender of the swimmers or the distance over which the readings were taken. E30. (ii) Although some candidates were aware that the collection of more data would be advantageous, their explanations were couched in terms of this extra data being in some way more precise or accurate than data collected less frequently. Few candidates noted that the extra data would provide information regarding the variation of force values in the swimmers dynamic situation or provide a more reliable average. It was clear that to most candidates reliability, accuracy and precision are the same thing. (iii) Although many responses were over-generalised, just under two-thirds of candidates scored the mark. Incorrect responses, apart from where the relationship between the variables had been misunderstood, were mostly in terms of factors for which there was no data provided, such as the swimmers mass, muscular strength, size of hands or swimming technique. (iv) Just over half of the candidates provided a correct answer to this question. Those failing to gain credit gave responses which ignored the request in the stem to consider only the data supplied, and referred to issues such as body mass or shape, improved exercise and training regimes, etc. (a) (ii) (b) E31. (i) Most candidates subtracted correctly to get the change in velocity, although quite a few multiplied 42 by 60 to get 2520. A significant minority worked out the 12 but then multiplied by 60 to get 720. Most candidates entered the correct values into the equation and completed the arithmetic correctly. Those candidates with an answer of 2520 or 720 for part (a)(i) were generally able to get the error carried forward mark. Less than half of the candidates knew the correct unit for acceleration. The majority of candidates incorrectly chose graph C. (a) Many students found it difficult to cope with three numbers. The main source of error was not calculating the change in velocity. Frequently 23/4 was incorrectly given as the acceleration. Most students either gave no unit or gave m/s. Just over a tenth of students scored all three marks. (b) This was poorly answered with few students scoring more than one mark. Many students seemed confused over the word ‘horizontal’ and subsequently gave some novel, but always wrong, reasons why a change in either the reaction or the weight would account for the acceleration. Many students read the question as ‘why do the forces change’ rather than ‘how the forces change’. Of those students who did write about the size of the forces most appreciated that the driving force had to increase. However most went on to write that friction decreased. It was rare to see both forces increasing and an appreciation that the driving force needed to be bigger than friction. E32. (a) Most students correctly chose B. Most students then realised that the gradient was the important feature of the graph to consider. Answers needed to be comparative so ‘steep line’ was not credited. Attempts at describing a gradient were often unsuccessful as no comparison with other sections of the graph was made. (b) It was disappointing that only two fifths of students could give the difference between velocity and speed. Many students gave velocity as the change of speed or the change of direction. (a) Nearly 60% of students scored all three marks. However, “standing still” or “stationary” was a common wrong answer to A, even though the students were told the car was moving. Often, in B and C, students calculated the resultant force and did not describe the motion, just the direction; forwards for B or backwards for C. E33. (b) (c) (i) Most students correctly gave the distance travelled while braking. Some students correctly wrote about the distance travelled after braking, or distance travelled in the braking time. A common wrong answer was to involve total distance travelled before the car stops, since this would include the reaction time. Many students lost the mark by putting a list of “braking and stopping distance”. (ii) Only 25% of students scored this mark. Students often wrote about factors affecting stopping and braking distance; ‘bad weather conditions’ was a very common wrong answer. Also tiredness, being drunk, condition of road and state of vehicle were often given. (i) This mark was for giving both 5000 N and a clear direction. A lack of a simple arrow drawn in the correct direction kept many students from gaining this mark. Some students simply wrote ‘a very large force’ rather than quantifying it. A common incorrect answer was “5000 N on the car”. One of the most common responses was “5000 N towards the car”, which gained credit. Some students failed to include 5000 N in their answer, just stating that the resultant force was equal and opposite. (ii) This question is about a dummy being used to measure/record the effects of impact/force. Many students wrote around this answer. “To see the force” was a common incorrect answer. Many students answered in terms of how much damage the dummy received, not mentioning measurement of the forces causing the damage and many students wrote about “impact”, instead of “force”, and did not gain credit for their answer. (iii) A great number of students knew how to find the gradient of a velocity-time graph in order to calculate the acceleration, However, they failed to use only the straight line part of the graph - between 2 and 4 seconds. As a result, 10/4 was a common answer, giving 2.5 instead of 4. Often, the unit was the only credit-worthy part of an answer, although there were a number of mps, mph, km/s, etc. An answer of 40 was also quite common, multiplying 10 by 4. About half the students gave the correct unit; although m/s was a common incorrect answer. Some students drew a triangle correctly, but failed to use it, gaining one mark only. Some students correctly found 2 and 8, or 1 and 4, but then didn’t know how to calculate the acceleration; obtaining 16 or 0.25. E34.This question on satellites was generally well answered although only under half of students could correctly link all the statements to the correct satellite in part (a). E35.This question on satellites was generally well answered although only under half of students could correctly link all the statements to the correct satellite in part (a).
