(i) A child stands at the centre of turntable with his two arms out stretched. The turntable
Channel: Doubtnut
Date: 2021-11-08

(i) A child stands at the centre of turntable with his two arms out stretched. The turntable is set rotating with an angular speed of 40 rpm. How much is the angular speed of the child if he folds his hands back and thereby reduces his moment of inertia to `(2)/(3)` times the initial value ? Assume that the turntable rotates without frictio(ii) Show that the child's new kinetic energy of rotation is more than the initial kinetic energy of rotation. How do you account for this increase in kinetic energy ?