(a) The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy ? Why ? (b) An object is dropped from a height h. When is its (i) potential energy maximum? (ii) kinetic energy maximum?


#1

(a) No, the total energy of the body is conserved as when a body falls down, its height from the ground decreases and hence its potential energy also decreases. Its velocity and kinetic energy increases. As a result, the decrease in the potential energy of a falling body appears as the gain in the kinetic energy of the body. The sum of the potential energy and kinetic energy of stalling body at any instant of time remains same.

(b) (i) Potential energy is maximum at height h.
(ii) Kinetic energy is maximum at ground level.