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When a person jump on a rotating merry go round, its angular velocity increases as he or she moves close to the center.
Finally, it stops due friction.
Can we apply the law of conservation of angular momentum in this case ?
- Jessie (age 15)
Auckland, New zealand
Yes, if you’re careful. Obviously the angular momentum of the merry-go-round plus person has changed when things come to a stop. The missing angular momentum must have been transferred to the Earth as a whole, which will then spin a tiny bit differently. However, that transfer occurs slowly. On a shorter time scale, the merry-go-round+person angular momentum is approximately conserved. So when the person moves toward the middle, lowering the moment of inertia, the angular speed must go up to keep the product constant.
(published on 07/11/07)
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