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

Explanation

As is known, work done `=` change is KE
`((1)/(2)mr^(2)omega^(2)=2pi^(2)mr^(2)x^(2))`
(i) When n is constant, KE is constant. Work done in zero.
(ii) When n is decreasing, KE decreases, work is done by the body.
(iii) When n is increasing, KE increases. Work is done on the body.