Question

A body of mass $m$ kg is rotating in a vertical circle at the end of a string of length $r$ metre. The difference in the kinetic energy at the top and bottom of the circle is

(a) $\frac{1}{2} m g r$

(b) $m g r$

(c) $2 m g r$

(d) $4 m g r$

Answer 1

The difference in the kinetic energy at the top and bottom of the circle is 2mgr. So, The correct option of this question will be (C).