1. A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is

2. A proton is kept at rest. A positively charged particle is released from rest at a distance d in its field. Consider two experiments; one in which the charged particles is also a proton and in another, a positron. In the same time t, the work done on the two moving charged particles is

3. A body of mass 20 kg is initially at a height of 3 m above the ground. It is lifted to a height of 2 m from that position. Its increase in potential energy is

4. A bicyclist comes to a skidding stop in 10 m. During this process, the force on the bicyclist due to the road is 200 N and is directly opposed to the motion. The work done by the cycle on the road is

5. A marble moving with some velocity collides perfectly elastically head-on with another marble at rest having mass 1.5 times the mass of the colliding marble. The percentage of kinetic energy by the colliding marble after the collision is

6. A uniform chain of length 2 m is kept on a table such that a length of 60 cm hangs freely from the edge of the table. The total mass of the chain is 4 kg. What is the work done in pulling the entire chain on the table?

7. An electric heater of rating 1000 W is used for 5 hrs per day for 20 days. The electrical energy utilised is

8. A body of mass 0.5 kg travels in a straight line with velocity v = ax^3/2 where a = 5 m^-1/2s^-1. The work done by the net force during its displacement from x = 0 to x = 2 m is

9. A ball is dropped from a height of 15 m. It gets embedded in sand by 10 mm and then stops. Which of the following is conserved?

10. A bullet is fired horizontally and gets embedded in a block kept on a table. If the table is frictionless, then

11. A pump delivers water at the rate of V cubic meter per second. By what factor its power should be raised so that it delivers water at the rate of nV cubic metre per second.

12. A man of 60 kg weight is standing at rest on a platform. He jumps up vertically a distance of 1 m and the platform at the same instant moves horizontally forward with the result that the man lands 1 meter behind the point on the platfrom from where the took the jump the total work done by the man at the instant he lands is

13. A body of mass 10 kg is moved parallel to the ground, through a distance of 2 m. The work done against gravitational force is

14. A body of mass 100 kg falls from a height of 10 m. Its increase in kinetic energy is

15. A shell is fired from a canon with a velocity v ms^-1 at an angle 6 with the horizontal direction. At the highest point in its path, it explodes into two pieces of equal mass. One of the pieces retraces its path to the canon and the speed of the other piece (in ms^-1) just after the explosion is

16. The work performed on an object does not depend upon

17. An electron and a proton are moving under the influence of mutual forces. In calculating the change in the kinetic energy of the system during motion, one ignores the magnetic force of one on another. This is because,

18. The slope of the potential energy versus position vector gives

19. If v be the instantaneous velocity of a body dropped from the top of a tower, when it is located at a height h, then which of the following remains constant?

20. A ball is dropped from a height of 1 m. If the coeffcient of restitution between the surface and ball is 0.6, the ball rebounds to a height of