Work, Energy, and Power Mock Test – Class 11 Physics

1. If the speed of a body is doubled while its mass remains unchanged, its kinetic energy becomes

2. In a head-on collision, two bodies approach with relative speed . If , their relative speed of separation is

3. A smooth ball strikes a fixed smooth wall obliquely with normal component and tangential component . If the coefficient of restitution is , the components just after collision are

4. Study the table about kinetic energy.

The row that needs correction is

5. A person holds a heavy suitcase at a fixed height for several seconds. In the elementary mechanical sense, the work done on the suitcase by the person's upward force is

6. A box is moved from the floor to a table high and then to a shelf high. Taking , the increase in gravitational potential energy from the table to the shelf is

7. The angle between a constant force and displacement is changed from to , while and remain unchanged. The work done becomes

8. A ball moves from point P to point Q near Earth's surface. Point Q is lower than point P. If the mass is and , the work done by gravity is

9. A constant net force acts on a body of mass , changing its speed from to over displacement . The derivation of uses along with

10. A particle has total mechanical energy . At a certain position, its potential energy is . Its kinetic energy at that position is

11. A body starts from rest under a variable net force. The area under its graph from to is . If the mass is , its speed at is

12. On a potential energy curve, a stable equilibrium point is usually represented by

13. A body initially at rest explodes into two fragments of masses and . The fragment moves to the right with speed . The velocity of the fragment is

14. A object is raised from to above the ground. Taking , the increase in gravitational potential energy is

15. A moving object of mass breaks into two fragments of masses and . Before breaking, it moves at . If the fragment moves forward at , the velocity of the fragment is

16. A force acts in the same direction as the velocity of a body moving at . The instantaneous power is

17. A collision or explosion problem is solved using only conservation of momentum. This is justified when

18. A cart moving at collides with a stationary cart. The carts stick together. The kinetic energy lost in the collision is

19. An ideal spring is compressed by in one case and stretched by in another case. The stored spring potential energies are equal because

20. A pendulum bob of mass is released from a height above its lowest point. At the lowest point, it collides and sticks to a stationary bob of mass . Taking , the speed of the stuck pair just after collision is

21. A ball moving with velocity strikes a fixed wall and rebounds with velocity . The coefficient of restitution for the ball-wall collision is

22. Read the case below and answer the question.

How should the work done by the three forces be classified?

23. A block moves along a horizontal surface under a applied force at above the horizontal. A friction force opposes the motion. The net work done on the block is

24. A motor of efficiency lifts a load upward through in . Taking , the input power of the motor is

25. A particle moves along the -axis under a net force described by , where is in and is in . If the particle starts from rest at and has mass , its speed at is

26. A cart moving at collides head-on with a cart initially at rest. If , the final velocities are

27. A device has constant power for . The energy transferred is represented by the area under its graph. The energy transferred is

28. Use the graph description below.

The powers in the two intervals are respectively

29. In a one-dimensional elastic collision, a moving body of mass with speed strikes a stationary body of mass . The final velocity of the initially stationary body is

30. Study the table for a curve.

The row that needs correction is

31. A block attached to a spring is pulled slowly from the natural position to . The spring constant is . The final spring force magnitude and the external work done are respectively

32. A object is thrown vertically upward with speed . Taking , its maximum height above the launch point is

33. A stationary object separates into two parts. Part P has mass , and part Q has mass . If part P moves with speed , the speed of part Q is

34. A body is thrown upward with speed . At a height above the launch point, taking , its kinetic energy is

35. The following statements refer to potential energy.
I. It is associated with configuration or position for conservative forces.
II. Its change satisfies .
III. Its zero level may be chosen conveniently.
IV. Only the absolute value of is physically meaningful, never the difference.
The true statements are

36. The work-energy theorem states that the net work done on a body is equal to

37. A body of mass starts from rest at . The net force acting along the -axis is , where is in and is in . Its speed at is

38. A block attached to a spring moves from to . The work done by the ideal spring force over this motion is

39. Study the collision records below.

The row that needs correction is

40. A body is displaced by while two constant forces and act on it. The net work may be written as

41. A stone held at a height above the ground has energy because of its position in Earth's gravitational field. This energy is an example of

42. A cart moving at collides elastically with an identical cart moving at in the same direction. What are the final velocities in the same order?

43. A smooth vertical motion problem is solved by two students using different zero levels for gravitational potential energy. If both use energy conservation consistently, their calculated speed at a given height will be

44. The efficiency of a machine is best defined as

45. A ball is dropped from height onto a fixed horizontal floor. If the coefficient of restitution is , the height reached after the second rebound is

46. A body moving east and the same body moving west with the same speed have

47. For a body moving near Earth's surface, the relation between work done by gravity and change in gravitational potential energy is

48. In a two-body system, the centre-of-mass velocity is most directly linked with

49. In a perfectly inelastic collision, total momentum is conserved but kinetic energy usually decreases. This decrease mainly appears as

50. Two carts collide on a frictionless horizontal track and stick together after impact. This collision is