Question

when does the body rotate

Answer 1

A body rotates when there is a net torque acting on it.To change the direction of rotation of a rotating body with fixed axis we will have to provide a retarding torque which will ultimately stop the rotation and will start it in the opposite direction. As a result the direction of rotation of the body will change. But if the axis is not fixed then the direction of rotation may be reversed simply by reversing the axis of rotation.

Answer 2

A body rotates when there is a net torque acting on it to change the direction of rotation of a rotating body with fixed Axis we will have to provide a retarding torque which will ultimately stop the rotation and will start it in the opposite direction as a result the direction of rotation of the body will change
Hope this helps you buddy