3. _______is defined as the time rate at which work is done or energy is transferred.

6.Ideally a _____ body is a body with a perfectly definite and unchanging shape. The distances between all pairs of particles of such a body do not change.

7. The notion of potential energy is applicable only to the class of forces where work done against the force gets ‘stored up’ as energy. When external constraints are removed, it manifests itself as _____ energy.

8. A stretched bow-string possesses ______ energy.

9. Coal consists of carbon and a ______of it when burnt releases about 3 × 10^7 J of energy.

11. In pure translational motion at any instant of time, all particles of the body have the same _____.

13. The total _______ energy of a system is conserved if the forces, doing work on it, are conservative.

14. To determine the motion of the centre of mass of a system no knowledge of _______ forces of the system is required.

15. The change in _____ energy of a particle is equal to the work done on it by the net force.