question_answer

A particle is moving in a circular path of a given radius with number of rotations per second (i) constant, (ii) increasing, (iii) decreasing. What happens to work done in the three cases?

Answer:

                Work is equal to the change in kinetic energy of the system, (i) In case speed is constant, kinetic energy does not change, hence work done is zero, (ii) when speed increases, K.E. increases, work is done by the exerting force, (iii) when speed decreases, K.E. decreases, work is done by the body on the force.