Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Cambridge TECHNICALS OCR LEVEL 2 CAMBRIDGE TECHNICAL CERTIFICATE/DIPLOMA IN SCIENCE PHYSICS IN SPORT R/505/3126 LEVEL 2 UNIT 14 GUIDED LEARNING HOURS: 60 UNIT CREDIT VALUE: 10 PHYSICS IN SPORT R/505/3126 LEVEL 2 AIM AND PURPOSE OF THE UNIT Participation in sport involves applying knowledge of the effect of forces. In some sports forces are used to cause an effect and in others they have to be overcome or compensated for in some way. The equipment used to improve performance, in some sports, has often been developed by using an understanding of the way in which forces behave. This unit considers some of the ways in which forces affect the motion of objects that are involved in different sporting activities. Learners will discover how understanding the effects that forces have on moving objects can assist the trainers of professional athletes and participants in sport such as archery, swimming, cycling, tennis, cricket and rowing to maximise their attainment. www.ocr.org.uk 2 Physics in Sport Level 2 Unit 14 ASSESSMENT AND GRADING CRITERIA Learning Outcome (LO) Pass Merit Distinction The assessment criteria are the pass requirements for this unit. To achieve a merit the evidence must show that, in addition to the pass criteria, the learner is able to: To achieve a distinction the evidence must show that, in addition to the pass and merit criteria, the learner is able to: The learner will: The learner can: 1 Understand the application of levers in sport. P1 apply knowledge of the science of levers to levers used in sporting situations M1 explain how changing the position of the load and effort changes the mechanical advantage of a lever, and how this is applied in sport 2 Know that forces affect the movement of objects in sport. P2 describe the different forces that affect the movement of objects in sport M2 describe how the resultant force affects the movement and speed of objects in sport 3 Know how to vary the effect of friction on moving objects. P3 describe the effect of streamlining an object and the different methods used in sport M3 apply knowledge of streamlining to a practical application in sport and justify how this could improve performance 4 Know how physics can be used to predict and improve techniques in sport. P4 describe conditions that make a moving object change its speed or the direction in which it moves M4 describe how the path of an object, moving at a constant speed on a frictionless surface, can be predicted 3 D1 analyse the link between force and rate of change of speed in different sporting contexts D2 describe how the independence of the vertical and horizontal motions of an object moving under the influence of gravity results in a parabolic path TEACHING CONTENT The unit content describes what has to be taught to ensure that learners are able to access the highest grade. Anything which follows an i.e. details what must be taught as part of that area of content. Anything which follows an e.g. is illustrative, it should be noted that where e.g. is used, learners must know and be able to apply relevant examples to their work though these do not need to be the same ones specified in the unit content. LO1 Understand the application of levers in sport. LO2 Know that forces affect the movement of objects in sport. • Measuring forces -- Forces are measured in Newtons (N) using, for example a spring balance. -- A mass of 1 kg experiences a force of 10 N due to the Earth’s gravitational field. • Friction -- When two surfaces move relative to each other there will be friction. -- Friction is a force. -- Frictional forces oppose the motion of an object. -- Friction will slow down a moving object. • Levers and forces -- Forces can produce a turning effect (for example the force applied to a bicycle pedal produces a turning effect). -- A lever is a machine made from a rigid rod or beam that can turn about a fixed pivot or fulcrum. -- A lever allows a force to be applied at one point but has an effect at a different point (for example when a rower pulls on one end of an oar, a force is applied to water at the opposite end of the oar). -- Terminology (i.e. the meaning of fulcrum, load, effort). -- The relative positions of the fulcrum and the points of application of load and effort may vary from one lever to another (a knowledge of the class of the lever is not required). -- Levers have a mechanical advantage that can be calculated using the formula, mechanical advantage = load ÷ effort. -- Changing the distance between the load and the fulcrum, the distance between the effort and the fulcrum or the size of the effort changes the size of the load that is applied by the lever. -- Changing the position of the load and effort changes the mechanical advantage of a lever. -- Use the formula (distance from fulcrum to load) x load = (distance from fulcrum to effort) x effort. • Gravity -- Some athletes use gravity in their sports, for example ski jumpers, divers and cyclists. -- Some athletes have to overcome the force of gravity, for example high jumpers, shot putters and weight lifters. • Resultant forces -- When forces of equal size act in opposite directions the resultant force is zero. -- Stationary objects will only move if a resultant force acts on it. -- The speed of a moving object, or direction of movement, will only change if a resultant force acts on it. -- An object moving at a steady speed travels equal distances in equal intervals of time. -- When a ball is kicked or hit with a raquet, forces change the speed and/or the direction of the ball because there is a resultant force. LO3 Know how to vary the effect of friction on moving objects. • Friction in fluids and gases -- Cyclists and swimmers are affected by frictional forces that can be described as drag, air resistance or fluid resistance, when they move through a liquid or gas. -- The size of the frictional force depends on the fluid or gas in which an object is moving and the shape of the object. • Levers in the human body -- Arms and legs function as levers (e.g. the arm lifting a load is a lever with the elbow as the pivot, the load is lifted in the hand and the effort is provided by the bicep muscle). -- In sport, competitors such as weightlifters, runners and swimmers use limbs as levers. www.ocr.org.uk • Reducing the effects of friction and terminal velocity -- The equipment used in cycling is designed to have a streamlined shape to reduce the drag on the cyclist. 4 Physics in Sport Level 2 Unit 14 -- Clothing worn by athletes in sports such as skiing, cycling and swimming is designed to have a smooth surface so that less resistance to movement is experienced. -- The conditions for terminal velocity i.e. frictional forces (e.g. air resistance) equal and opposite to driving forces (e.g. Force applied by a cyclist), and how streamlining can increase the top speed of an athlete. LO4 Know how physics can be used to predict and improve techniques in sport. • Monitoring the effect of forces on the speed and direction of a moving ball -- The horizontal distance travelled by a tennis or cricket ball, can be calculated using a formula i.e. distance travelled = speed x time taken. -- The vertical distance travelled by an arrow or ball falling under the influence of gravity from rest can be calculated using a formula i.e. distance fallen = 5 x (time taken)2 • The independance of horizontal and vertical motion -- The vertical motion of an arrow, ski jumper or ball has no effect on its horizontal motion. -- Illustrate knowledge of the parabolic path taken by an object moving at a steady speed horizontally and accelerating vertically. • Using systems to predict the path that will be taken by a moving object -- The use of ‘Hawk-Eye’ in cricket and tennis to predict the trajectory of a ball and how this can be used to inform lbw decisions in cricket and line calls in tennis. -- The use of ‘Hawk-eye’ in post event analysis for training purposes. 5 DELIVERY GUIDANCE LO1 Understand the application of levers in sport be tightened fully using the fingers but can by using a lever in the form of a stud spanner, leading to an appreciation that a lever can be used to apply a load that is greater than the effort when used as a force multiplier. As an introduction to the unit, learners could use a spring balance or newtonmeter to measure the downward force on objects that have a known mass. The data collected could be tabulated and analysed using graphical and/or mathematical techniques to establish that the force, in newtons, with which gravity pulls an object downwards, can be calculated by multiplying its mass, in kilogrammes, by 10. In part 3 of LO1 learners could consider parts of an athletes body, for example the arm, that function as levers and the advantages of participants, in a range of sports, having long limbs and ways in which athletes can use levers in, for example, pole vaulting, judo and wrestling. In the second part of LO1, learners could, by working indiviually, identify scenarios in sport where objects are made to turn or rotate. They could then continue, using a combination of prior knowledge and research to identify the mechanism that causes the rotation. Through the medium of small group discussion learners could then try to identify what all the mechanisms identified have in common, leading to an understanding that forces can produce a turning effect. Learners could be shown how to apply the formula (distance from fulcrum to load) x load = (distance from fulcrum to effort) x effort to estimate the force applied by the bicep muscle in lifting a known weight. LO2 Know that forces affect the movement of objects in sport. Learners could be asked to predict and explain what would happen to a cricket ball or football as it rolls across a flat surface and design a simple experiment to test their prediction. This could lead to the formal teaching that friction is a force that opposes motion and slows down a moving object. Learners could research how friction affects cyclists and swimmers. Learners could be introduced to levers through formal teaching using examples selected from different sports, for example cycling and rowing and identifying what is meant by the terms; fulcrum, load and effort for a range of levers. Through practical experience learners could discover that when a force is applied to one part of a lever the lever turns and another part of the lever can be used to apply a force at a different place. Learners could then identify sporting situations where a lever is used in this way, for example in weight-training machines and rowing. In the second part of LO2 learners could be taught that gravity is a force that pulls an object downwards Learners could adopt the role of a participant in a specific sport and debate, in small groups, whether gravity is a friend or foe. Learners could produce a balanced written report of their discussion. Learners could investigate experimentally how the size of the forces involved and the distances from the pivot to the points at which the forces act are related. This could be done using weights hanging from metre rules supported by a suitable pivot. Learners’ experiments could lead to an appreciation of how the ratio of load to effort (mechanical advantage) is affected by the distances between the forces and the fulcrum. The formula (distance from fulcrum to load) x load = (distance from fulcrum to effort) x effort could be verified experimentally by learners. Learners could be formally taught the meaning of the term resultant force. By observation of a puck used in an ice hockey game learners could discover that objects carry on moving at a steady speed, without changing direction, unless a resultant force acts on them. Learners could discover, experimentally or from past experience, how to make a ball or other object speed up (accelerate), slow down (decelerate) or change direction by applying forces or bouncing from surfaces and relate their findings to the movement of athletes or objects in a range of sports such as squash, tennis, ice hockey, cricket, indoor football and basketball. Learners could produce a short video, to be used by a fitness instructor, to demonstrate the use of a weight-training machine. This could include showing how applying forces to different points on the equipment’s levers could be used to vary the amount of effort used to lift a load. Learners could research situations in sports where levers are used e.g. when football boots have screw in studs that cannot www.ocr.org.uk 6 Physics in Sport Level 2 Unit 14 As an introduction to the final part of LO2 learners could identify examples, from different sports, where objects stop suddenly when they are involved in impacts and those where they rebound. could be explained by learners in the context of a sky diver in free fall. Learners could research the way in which a sky diver can increase or decrease their terminal velocity by changing their body shape and produce a leaflet that an instructor could use to support the training of novices. Learners could be taught that when a moving object is stopped it experiences a force and that the size of this force depends on the rate at which its velocity changes (deceleration). Learners could be taught that the ideas that they have used to explain the motion of a sky diver can be applied to the movement of a swimmer or cyclist in which a terminal velocity is reached when the driving force produced by the athlete is equal to the frictional force acting on the athlete. Learners could be guided to appreciate that the athlete’s speed can only become higher by the athlete providing a bigger driving force and/or a reduction in the frictional force. Learners could be taught that to calculate the force involved use the equation: force = (mass of object x change in velocity) ÷ time taken to stop Learners could use this equation to explain why, when a moving object is stopped over a long period of time, the force involved is smaller than if the same object is stopped, from the same speed, in a shorter time. Learners could research the design of landing areas for pole vaulters and produce a report for an athletics club recommending a suitable system to use. In different sporting contexts, learners could identify whether reducing friction, in this way, could increase the performance of athletes. They could research the ways in which different sports have attempted to improve performance by reducing frictional forces and evaluate the effectiveness of these attempts. e.g. the improvements seen in British cycling achievement in recent years. Learners could research the way in which designers work with athletes and their coaches to develop new clothing to enhance performance. LO3 Know how to vary the effect of friction on moving objects. Learners could be introduced to friction in fluids by, for example, studying small objects of varying shapes and masses falling through a viscous liquid in a tall jar and through air. Learners could be guided to appreciate that an object falls more slowly through the liquid than through air and recognise that increased friction in the liquid is responsible for the difference in behaviour. LO4 Know how physics can be used to predict and improve techniques in sport. Learners could be introduced to the analysis of an object’s motion by using the formula distance travelled = speed x time taken to calculate the position of an object moving at a constant speed in a straight line at some time in the future. They could then be taught that the position, at some time in the future, of an object falling under the influence of gravity on Earth can be calculated using the equation: distance fallen = 5 x (time taken)2 Learners could compare the time taken, to fall through a viscous liquid, for objects with the same mass but different shapes to discover the effect of shape on the size of the fritional force. By using their observations of objects moving through a viscous liquid learners could investigate how a designer could reduce the force of friction by changing the shape of an object. Learners could use a spreadsheet to calculate the position of an object at a large number of times in the future for both horizontal and vertical motion. They could display the calculated data graphically and use extrapolation to predict the behaviour of the object further into the future. Learners could be taught formally how the size of the frictional force depends on the speed and shape of the object and the material that it is moving through. Learners could observe, using commercially available apparatus, that the horizontal motion of an object is not affected by any vertical motion. A ball bearing projected horizontally must hit the ground at exactly the same time as one that is dropped vertically from the same height at the same time because the sound of only one impact with the ground is heard. Learners could be encouraged to apply their knowledge of forces to this situation by considering any changes in the direction and size of the forces of gravity and friction as the object falls and how this affects the resultant force. Learners could be guided to an understanding that when an object’s speed increases so does the frictional force and that the object only accelerates until the two forces have the same size. The conditions under which terminal velocity is reached A spreadsheet could be used to allow learners to combine the 7 effects of horizontal and vertical motions to predict the path of a projectile, by drawing a graph showing the projectiles horizontal and vertical positions as it follows a parabolic path. The graph can be projected onto a screen and, with practice, learners can show that an object thrown horizontally at the correct speed will follow the curve predicted theoretically. Learners could be taught formally how an archer allows for the fall of an arrow, as it follows a parabolic path from bow to target, when taking aim. Using systems to predict the path that will be taken by a moving object could be introduced by learners viewing a video of an object moving at a steady speed against a suitable scale. They could look at the video, frame by frame, and predict the position of the object in the next frame. They could discuss why the relatively small number of frames recorded per second, when using a domestic video camera, does not allow fast moving objets to be monitored easily and be guided in research to discover how this short-coming could be overcome. Learners could research and produce a report on the development of the ‘Hawk-eye’ system that has been designed to predict the behaviour of the ball in, for example, cricket and tennis. They could be asked to describe its component parts, the need for the precise positioning of the cameras used, the methods used to process data and identify any developments, in this field, that can be expected in other sports, for example football, in the future. Any limitations of the system could be considered. Learners could complete their report by describing how a professional coach may use the analysis of the behaviour of moving objects to improve the technique of an athlete. www.ocr.org.uk 8 SUGGESTED ASSESSMENT SCENARIOS AND GUIDANCE ON ASSESSMENT Criteria Assignment Scenario Assessment LO1 Are long oars the best? Learners could plan and carry out an experiment to find out how changing the position of the fulcrum of an oar used in rowing affects the size of the force acting at the blade end of the oar when the force at the rower’s end is kept constant. A plan should be produced by the learner prior to starting any experimental work. The assessment could be in the form of a plan, record of the data gathered and evidence of processing. Learners could be presented with suitable moving pictures of; balls being hit by a bat, stick, foot, raquet, club or similar, objects slowing down due to friction and athletes being stopped suddenly, in different sporting situations. They could be asked to identify situations where objects slow down, speed up or stop and explain the role played by forces in each event, including how the effect of the forces can be minimised or maximised. The assessment could be in the form of a table that identifies the scenario, the behaviour of the object and details relating to the forces involved. LO2 Forces and motion P1 A learner will do the experiment, with help if necessary, record the results obtained, and attempt to identify a pattern in the data, leading to a conclusion which answers the question posed ‘Are long oars the best?’. M1 The learner will use their results to identify a quantitative relationship between load and effort and will appreciate the conditions in which the position of the fulcrum will result in the load being less than the effort. P2 A learner will be able to name forces such as gravity and friction and give an explanation of the role played by forces in some of the scenarios. M2 A learner will be able to use their knowledge of friction to explain, for example, why a cricket ball may stop before reaching the boundary and why sweepers using brooms are part of a curling team. It is expected that learners will describe how the resultant force affects the movement and speed of objects in the examples they give. D1 In addition to the above the table produced by learners should include an analysis of the link between force and rate of change of speed in the examples given. LO3 Friction and performance www.ocr.org.uk Learners could be given the task of proposing changes to style and equipment that a down hill skiing team could adopt in a drive to increase average speeds in competition and give reasons for their poposals. 9 Learners could produce a report identifying what should be changed and why P3 Learners should identify at least two realistic ways of increasing perfomance including one that involves reducing friction by making the athlete more streamlined in some way. M3 The learner should produce a report, in which the science is correct, about how frictional forces could be reduced by adopting a range of adaptations. Physics in Sport Level 2 Unit 14 LO4 Improving techniques Learners could be asked to produce briefing material to encourage sport coaches to consider the physics in sport in order to improve the techniques of those they coach e.g. cricket bat positioning when hitting a ball, tennis racquet positioning when hitting a ball, technique involved in throwing a shot in a shot-put. 10 P4 In applying their knowledge of predicting the movement of objects in sport a learner should describe the conditions that make a moving object change its speed or the direction in which it moves. M4 In the briefing material a learner must include a description of how the path of an object, moving at a constant speed on a frictionless surface, can be predicted and highlight the benefits to the coaches of being able to do this. D4 The learner will illustrate knowledge of the parabolic path taken by an object moving at a steady speed horizontally and accelerating vertically, using the correct terminology. CONTACT US Staff at the OCR Customer Contact Centre are available to take your call between 8am and 5.30pm, Monday to Friday. We’re always delighted to answer questions and give advice. Telephone 02476 851509 Email [email protected] www.ocr.org.uk