A ballet dancer, dancing on a smooth floor is spinning about a vertical axis with her arms folded with an angular velocity of 20 rad/s. When she stretches her arms fully, the spinning speed decrease in 10 rad/s. if I is the initial moment of inertia of the dancer, the new moment of inertia is

Q: A ballet dancer, dancing on a smooth floor is spinning about a vertical axis with her arms folded with an angular velocity of 20 rad/s. When she stretches her arms fully, the spinning speed decrease in 10 rad/s. if I is the initial moment of inertia of the dancer, the new moment of inertia is

(a) 2 I

(b) 3 I

(c) I/2

(d) I/3

Ans: (a)