题目内容
如图所示,一细绳跨过一个光滑的质量可以忽略的定滑轮,两端分别系上质量为M和m的物体,且M>m,M静止于地面上,当m自由下落h后绳子才被拉紧,求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241158286421540.gif)
(1)绳子被拉紧后的瞬间,两物体的速度是多少?
(2)M上升的最大高度是多少?(m下降的过程中不会碰地)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241158286421540.gif)
(1)绳子被拉紧后的瞬间,两物体的速度是多少?
(2)M上升的最大高度是多少?(m下降的过程中不会碰地)
(1)
(2)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115828674534.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115828658598.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115828674534.gif)
(1)(M+m)v'=mv,
∴v'=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241158286891291.gif)
(2)MgH=mgH+
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115828705960.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115828720949.gif)
∴H=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241158287361417.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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