Question

A person sitting firmly over a rotating stool has his arms stretched. If he folds his arms, his angular momentum about the axis of rotation

(a) increases
(b) decreases
(c) remains unchanged
(d) doubles

Answer 1

Answer ⇒ Option (c) .

A person sitting firmly over a rotating stool has his arms stretched. If he folds his arms, his angular momentum about the axis of rotation will ''remains unchanged''

Explanation ⇒ According to the question, there is no external torque.

Now, we know that if there is no external torque then the angular momentum is conserved.

Hence, Option (c). is correct.

Hope it helps.