Download Worksheet Physics Class IX

Worksheet Physics Class IX Q1. Name the force which is responsible for change in position or state of an object. Q2. Find the weight of a 80 kg man on the surface of moon ? What should be his mass on the earth and on the moon ? (ge = 9.8 m/s2 ; gm=1.63 m/s2) Q3.Study the given graph and answer the following questions. (i)
Which part of the graph shows accelerated motion ? (ii) Which part of the graph shows retarded motion ? (iii) Calculate the distance travelled by the body in first 4 seconds of journey (ii) Which part of the graph shows retarded motion ? (iii) Calculate the distance travelled by the body in first 4 seconds of journey graphically ? Q4.A man weighing 60 kg runs along the rails with a velocity of 18 kmh 1 and jumps into a car of mass 1 quintal (100 kg) standing on the rails. Calculate the velocity with which car will start travelling along the rails Q5 State reason for the following : (a) All the cars are provided with seat belts (b) It is dangerous to move out of a moving bus (c) Road accidents at high speeds are very much worse than accidents at low speeds. Q6 A stone is thrown vertically upwards with a velocity of 40 m/s and is caught back. Taking g 10 m/s2, calculate the maximum height reached by the stone. What is the net displacement and total distance covered by the stone ? Q 7 (a) Differentiate between uniform linear and uniform circular motion. (b) Write any four examples of uniform circular motion. (c) Is uniform circular motion accelerated motion ? Q8 (a) Differentiate between speed and velocity. (b) When is a body said to have uniform velocity ? (c) How can we describe the position of an object ? Illustrate with suitable Q9 State Newton’s second law of motion and show that the first law of motion can be mathematically stated from the mathematical expression for the second law of motion. (b) A stone dropped from a window reaches the ground in 0.5 seconds (given g 10 ms 2) (i) Calculate the speed just before it hits the ground. (ii) What is the average speed during 0.5 ? (iii) Calculate the height of window from the ground. Q10 State Newton’s second law of motion and show that the first law of motion can be mathematically stated from the mathematical expression for the second law of motion. (b) A stone dropped from a window reaches the ground in 0.5 seconds (given g 10 ms 2) (i) Calculate the speed just before it hits the ground. (ii) What is the average speed during 0.5 ? (iii) Calculate the height of window from Q11 (i) Name the property of bodies to resist a change in their velocity. (ii) What is relationship between force and acceleration ? (iii) What name is given to the product of mass and velocity of a body ? (iv) Which physical quantity corresponds to the rate of change of momentum ? (v) Name the principle on which a rocket works. Q12 State universal law of gravitation. Write S.I. unit of ‘G’. Q13 Define distance and displacement. A body covers one complete revolution around a circular park of circumference 176 m in 4 minutes. Find the displacement of the body after 6 minutes. Q14 When a fast moving horse stops suddenly a careless rider falls in the forward direction. Give reason for it. Q15 A car starts from rest and rolls down a hill with constant acceleration. It travels a distance of 800 m in 10 seconds. Find its acceleration. Also, find the force acting on it if its mass is 800 kg. Q16 Define mass and weight of an object. Write their S.I. units. An object has mass of 20 kg on earth. What will be its mass and weight on the surface of the moon ? (g on moon 1.6 m/s2) Q17 Q..Derive second equation of motion. S =1 /2 ut +at2 graphically where the symbols have their usual meanings. (b) A car accelerates uniformly from 18 km/h to 36 km/h in 5 seconds. Calculate the acceleration and the distance covered by the car in that time. Q18 .What is meant by free fall? A ball is dropped from the roof of a building. It take 10 seconds to reach the ground. Find the height of the building (a) State law of conservation of momentum. Write S.I. unit of momentum. (b) Two cars each of mass 1000 kg are moving in a straight line but in opposite directions. The velocity of each car is 5 m/s before the collision during which they stick together. What will be the velocity of the combined cars after collision. Q 19 Define one Newton of force Q20 What is meant by free fall? A ball is dropped from the roof of a building. It take 10 seconds to reach the ground. Find the height of the building. Q21 A swimmer is able to swim in a forward direction in a swimming pool only when he is pushing the water in the backward direction. Give reason for the above mentioned statement and justify the same. Q22 An auto driver moving with a speed of 36 km/h sees a child standing in the middle of the road. He applies break and brings his vehicle to rest in 5 seconds just in time to save the child. If the total mass of the auto and the driver be 450 kg then calculate the force of brakes. Q23 Two bodies ‘P’ and ‘Q’ having masses m1 and m2, when separated by a distance d1 exert a force ‘F’ on each other. What happens when (a) masses of both the objects are doubled. (b) distance between the two bodies is reduced to half. (c) the space between the two objects has no air and it is complete vacuum. Q 24A stone is dropped from a height of 10 m on an unknown planet having g = 20 m/s2. Calculate the speed of the stone when it hits the surface of the planet. Also calculate the time it takes to fall through this height Q 25 (a) Define momentum. Write its S.I. unit. (b) How much momentum will an object of mass 10 kg transfer to the floor, if it falls from a height of 5m (g =10 m/s2). (c) Explain how a karate player can break a pile of tiles with a single blow of his hand.