题目内容
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241206214171105.gif)
如图,让质量m=5kg的摆球由图中所示位置A从静止开始下摆。摆至最低点B点时恰好绳被拉断。设摆线长
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120621432185.gif)
求:(1)绳子所能承受的最大拉力T
(2)摆球落地的速率v
(1) 100N
(2) 8m/s
(2) 8m/s
(1)小球A到B过程机械能守恒:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120621448795.gif)
B点时,F向=T-mg=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120621604416.gif)
由①、②得T=2mg=100N
(2)小球A到C过程机械能守恒:mghA=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120621620425.gif)
hA=OC-lcos60° ④ 由③、④得:v=8m/s
![](http://thumb2018.1010pic.com/images/loading.gif)
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