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 decreases to 10 rad/s. If I is the initial moment of inertia of the dancer, the new moment of inertia is

A ballet dancer, dancing on a smooth floor is spinning about a vertica

1.	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 decreases to 10 rad/s. If I is the initial moment of inertia of the dancer, the new moment of inertia is
Answer» 2I 3 I I/2 I/3 Solution :Here , angular momentum is CONSERVED . Initial angular momentum = Final angular momentum `I xx 20 = I.xx 10` (where I. is new MOMENT of inertia.) I. = 2I