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What should a person on a freely rotating turn table do to decrease his (angular) speed ?
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- Bring his hands together
- Raise his hands up
- Spread his hands outwards
- Sit down with raised hands
- Bring his hands together
Correct Option: C
The answer is related to the conservation of angular momentum. The person on the rotating table will maintain approximately the same angular momentum during the spin. If he moves his arms in, it will reduce the rotational inertia by reducing the distance of the mass of her arms and hands from the axis of rotation. In order to maintain the same angular momentum, angular rotation is increased. However, when he spreads his hands outward, the angular rotation is decreased. The spin becomes slower.
