A child stands at the centre of a turn table with his two arms outstretched.
Channel: Doubtnut
Date: 2020-08-02

A child stands at the centre of a turn table with his two arms outstretched. The turn table 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 reducing the moment of inertia to `(2//5)` time the initial value ? Assume that the turn table rotates without friction.  (b) Show that the child's new `K.E.` of rotation is more than the initial `K.E.` of rotation. How do you account for this increase in `K.E.` ?