**Short Questions**

1. A 20g ball hits the wall of a squash court with a large force of 50 N.If of impact of force is 0.5 sec.Find the impulse?

2. A body is moving along a circle with a constant speed,is it moving with uniform velocity?

3. A man standing on the t op of a tower a ball straight up with initial velocity vi and at the same time throws a second ball straight downward with the same speed which ball will have larger speed when it strikes the ground ignore air friction?

4. An object is thrown vertically upward.Discuss the sign of acceleration due to gravity relative to velocity while the object is in air?

5. At what point or points in its path does a projectile have its minimum speed its maximum speed?

6. Can the velocity of an object reverse the direction when acceleration is constant? If so, give an example.

7. Can there be an acceleration when a body is moving with constant speed?

8. Define ballistics flight and ballistic trajectory.

9. Define elastic collision?

10. Define isolated system with suitable example?

11. Define momentum and write down its unit.

12. Define Momentum?

13. Define motion with a suitable example?

14. Define projectile motion?

15. Describe two uses of ballistic missiles?

16. Differentiate between elastic and inelastic collisions?

17. Discuss the importance of the velocity-time graph?

18. Discuss the sign of acceleration due to gravity, relative to velocity, while the object is in air.

19. Explain impulse?

20. Explain the circumstances in which the velocity v and acceleration a of a car are: (i)Parallel (ii) Anti-parallel (iii) Perpendicular to one another?

21. Explain the circumstances in which the velocity v and acceleration of a car are perpendicular to one another.

22. Explain the difference between elastic and inelastic collisions.Explain how wold a bouncing ball behave in each case?

23. Explain the significance of mass of a moving body?

24. Find the dimensional formula for impulse?

25. If two balls of equal masses one at rest and other ball is moving with velocity v.if the moving ball collide with the ball at rest what will happen?

26. In the expression of Newton’s second law F= ma,Let F =0 give your comments about new situation?

27. Is it possible for a body to have acceleration when moving with. (a) constant velocity (b) constant speed

28. Motion with constant velocity is a special case of motion with constant acceleration. Is this statement true?

29. Motion with constant velocity is a special case of motion with constant acceleration.Is this statement true?

30. Show that the weight of a freely falling body is zero?

31. Sketch a graph showing positive and negative accelerations in a particular moving object?

32. State law of conservation of momentum?

33. State Newton’s second law of motion in terms of momentum?

34. State Newton’s first and second law of motion.

35. State the law of conservation of linear momentum pointing out the importance of isolated system?

36. State the law of conversation of linear momentum.

37. State the law of motion in terms of momentum.

38. Under what condition average velocity and instantaneous velocity are equal?

39. Under what condition, the instantaneous and average velocities of a moving object becomes equal

40. What are the factors upon which force due to water flow depend?

41. What do you understand by the time of flight?

42. What happens when a very heavy ball collides with light stationary ball?

43. What is ballistic missile?Define its trajectory?

44. What is horizontal range?

45. What is projectile motion? In what direction acceleration is zero in this motion.

46. What is the average acceleration in the velocity time graph?

47. What is the ballistic flight?

48. What is the change in total energy during elastic or inelastic collisions?

49. What is the difference between inertial frame of reference and non-inertial frame of reference?

50. What is the difference between uniform and variable velocity?

51. What is the distance covered in the velocity-time graph?

52. What is the maximum height of projectile?

53. What is the physical signification of momentum?

54. What is the principle of rocket motion.How can it be applied on its motion to gain the escape velocity?

55. What point or points in its path does a projectile have its minimum speed, its maximum speed?

56. When a body is dropped from a height 4m, calculate its velocity?

57. When light body collides with massive body at rest what will happen to the light body?

58. Why a safety helmet of a motor cycle’s is padded?

59. Why do you keep your lags far apart when you have to stand on the floor of a moving train?

60. Why does a rifle move backward when bullet is fired discuss it with reference to momentum?

61. Why is the first law of motion also called law of inertia?

62. Write any two properties of an inertial frame of reference?

**Long Questions**

1. Define impulse and show that how it is related to linear momentum?

2. State the law of conservation of linear momentum, pointing out the importance of isolated system. Explain, why under certain conditions, the law is useful even though the system is not completely isolated?

3. Explain the difference between elastic and inelastic collisions. Explain how would a bouncing ball behave in each case? Give plausible reasons for the fact that K.E is not conserved in most cases?

4. Explain what is meant by projectile motion. Derive expressions for (A) the time of flight (B) the range of projectile Show that range of projectile is maximum when projectile is thrown at an angle of 45o with the horizontal.

5. At what point or points in its path does a projectile have its minimum speed, its maximum speed?

6. Prove that change of momentum is the impulse?

7. State Newton‟s second law of motion and define S.I unit of force?

8. Define average and instantaneous velocities of the moving body. Under what condition they are equal.

9. Explain the difference between Elastic and inelastic collision?

10. Define impulse and derive its dimensions?

11. Find relation for force due to water flow.

12. Find the angle of projectile for which its maximum height and horizontal range are equal.

13. Show the acceleration and distance covered by a body can be measured from velocity time graph?

14. Write any properties of inertial frame of references.

15. Define an isolated system? State and prove law of conservation of linear momentum.

16. Explain elastic collision in one dimension and derive the relation for relative velocities of two bodies after collision.

17. Explain elastic collision in one dimension and drive the relation When m₁= m₂ and m₁>> m₂

18. Define projectile motion. Derive expressions for maximum height and time of flight for projectile.

19. Define projectile motion. Derive expressions for maximum height, range and maximum range.

20. A helicopter is ascending vertically at the rate of 19.6 ms⁻¹ when it is at a height of 156.8 m above the ground, a stone is dropped. How long does the stone take to reach the ground?

21. A proton moving with the speed of 1 x 10⁷ms⁻¹ passes through a 0.02 cm thick sheet of paper and emerges with speed of 2 x 10⁶ ms⁻¹. Assuming uniform deceleration, find retardation and time taken to pass through the paper.

22. Two masses m₁ and m₂ are initially at rest with a spring compressed between them. What is the ratio of their velocities after spring has been released.

“23. An amoeba of mass 1 x 10⁻¹² kg propels itself through water by blowing a jet of water through a tiny orifice. The amoeba ejects water with a speed of 1 x 10⁻⁴ ms⁻¹ at a rate of 1x 10⁻¹² kg/s. Assume that the water is continuously replenished so that the mass of the amoeba remains the same.

(a) If there were no force on amoeba other then the reaction force caused by the emerging jet, what would be the acceleration of the amoeba?

(b) If amoeba moves with constant velocity through water, what is force of surrounding water (exclusively of jet) on the amoeba?”

24. A boy places a fire cracker of negligible mass in an empty can of 40g mass. He plugs the end with a wooden block of mass 200g. After igniting the fire cracker, he throws the can straight up. It explodes at the top of its path. If the block shoots out with a speed of 3ms⁻¹, how fast will the can be going?

25. A truck weighing 2500 kg and moving with a velocity of 21 ms⁻¹ collides with stationary car weighing 1000 kg. The truck and the car move together after the impact. Calculate their common velocity.

26. Two blocks of masses 2 kg and 0.5 kg are attached at two ends of a compressed spring. The elastic Potential Energy stored in the spring is 10J. Find the velocities of the blocks if the spring delivers its energy to the blocks when released.

27. A football is thrown upward at an angle of 30 degree with respect to the horizontal. To throw a 40 m pass what must be the initial speed of the ball?

28. A ball is thrown horizontal from a height of 10m with velocity of 21ms⁻¹. How far off will it hit the ground and with what velocity?

29. A bomber dropped a bomb at a height of 490m when its velocity along the horizontal was 300 kmh⁻¹. (a)How long was it in air? (b) At what distance from the point vertically below the bomber at the instant the bomb was dropped, did it strike the ground?

30. Find the angle of projection of a projectile for which its maximum height and horizontal range are equal.

31. Prove that for angle of projection, which exceed or fall short of 45 degree by equal amount the ranges are equal.

32. A SLBM (submarine launched ballistic missile) is fired from a distance of 3000km. If the earth were flat and the angle of launch is 45 degree with horizontal, find the velocity with which the missile is fired and the time taken by SLBM to hit the target