Important Questions CBSE Class 9th : Physics Year 2009

(Unsolved)

Q. 1. How much force is needed to accelerate a trolley of mass 20g through 1 m/s2?

Q. 2. A force of 100N acts on a mass of 25 kg for 5 s .What velocity does it generate?

Q. 3. A bullet leaves a rifle with a velocity of 100m/s and the rifle of mass 2.5 kg recoils with a velocity of 1m/s. Find the mass of the bullet?

Q. 4. A certain force acting on a mass of 15kg for 3s, gives it a velocity of 2m/s. Find the magnitude of force?

Q. 5. A cricket ball of mass 0.15 kg is moving with a velocity of 1.2m/s . Find the impulse on the ball and average force applied by the player if he is able to stop the ball in 0.18s?

Q. 6. A motor car of mass 200kg is moving with a certain velocity . It is brought to rest by the application of brakes, within a distance o f 20m when the average resistance being offered to it is 500N.What was the velocity of the motor car?

Q. 7. A body of mass 0.5kg undergoes a change of velocity of 4cm/s in 4s What is the force acting on it?

Q. 8. A force of 8N acting on an 8kg mass for 4s provides its some velocity.Calculate the velocity?

Q. 9. What would be the weight of a body of mass 50kg on the surface of the moon, where g = 1.6m/s2 what would be its mass?

Q. 10. A boy jumps a distance of 2m on the surface of the earth. What distance will he jump on the surface of the moon where g is 1/6th of the value on the surface of the earth?

Q. 11. Two bodies of mass 1kg and 2 kg moving in the direction opposite to each other with a speed 5m/s collide. Calculate the total momentum of the system before collision?

Q. 12. A bullet of mass 15g leaves the barrel of a gun with a velocity of 120m/s.The gun recoils with a velocity of 1m/s. Find the mass of the gun?

Q. 13. A force of 3N acts on a mass of 0.5kg at rest for 10s. Find the final velocity and the momentum of the body after 10s?

Q. 14. A force of 80N acting on a certain mass for 3s gives it a velocity of 6m/s. find the mass of the body if the body was initially at rest?

Q. 15. A toy of mass 0.1kg acquires a spped of 5 m/s when pushed forward. Ahat is the impulse given to the toy?

Q. 16. A projectile weighing 200kg is fired from a gun with a velocity of 500m/s. If the velocity of recoil of the gun is 12.5m/s calculate the mass of the gun?

Q. 17. A car of mass 2500kg accelerates at the rate of 4m/s2 and then at the rate of 16 m/s2. Calculate t6he ratio of the forces exerted by the engine in the two cases?

Q. 18. A driver accelerates his car first at the rate of 1.8m/s2 and then at the rate of 1.2m/s2 calculate the ration of the forces exerted by the engines?

Q. 19. A body of mass 5 kg undergoes a change in speed from 30 to 40m/s . calculate its increase in momentum?

Q. 20. A body of mass 100g is moving with a velocity of 15m/s Find the momentum associated with the ball?

Q. 21. body of mass 5 kg is moving with a uniform velocity of 10m/s It is acted upon by a force of 20N What will be its velocity after 1s?

Q. 22. In order to gain a velocity of 12m/s how long should a force of 30N be exerted on a body of mass 5kg?

Q. 23. The velocity of a body of mass 5kg reduces from 10 m/s to 5 m/s. What is the change in momentum of the body?

Q. 24. A 5 kg rifle fires a 10g bullet at a velocity of 500m/s find the recoil velocity of the rifle?

Q. 25. A block of mass 3kg has a velocity of um/s. When a force of 18N acts on the block, it reduces the velocity from U to U/2 after the block has covered a distance of 9 m . Find U?