| conservation of angular moment |
| 送交者: newbigman 2013年06月11日06:26:29 于 [灵机一动] 发送悄悄话 |
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If you tie a ball with string to a central pillar. Hit the ball in the circular direction. The ball will rotate around the pillar and the string will get shorter.
If the initial speed of the ball is 10m/s, initial free length of the string is 1m. What is the speed of the ball, once the free length of the spring changed to 0.5m?
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