题目内容
如图所示,光滑圆柱半径为R,被固定在水平平台
上,用轻绳跨过圆柱体与两小球m1、m2相连(m1、m2分别为它们的质量),开始时让m1放在平台上,两边绳绷直,两球从静止开始m1上升,m2下降.当m1上升到圆柱的最高点时,球m1对轨道的压力0.2m1g,求:
(1)小球m1上升到圆柱的最高点时,速度多大?(用g、R表示)
(2)两球从静止开始至m1上升到圆柱的最高点,系统减少的势能为多少?
(3)m2应为m1的多少倍?![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241223418294110.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082412234181485.gif)
(1)小球m1上升到圆柱的最高点时,速度多大?(用g、R表示)
(2)两球从静止开始至m1上升到圆柱的最高点,系统减少的势能为多少?
(3)m2应为m1的多少倍?
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241223418294110.jpg)
(1)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341845405.gif)
(2)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241223418611135.gif)
(3)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341876592.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341845405.gif)
(2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241223418611135.gif)
(3)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341876592.gif)
(1)当m1上升到圆柱的最高点时,
(2分)
(1分)
(2)两球从静止开始至m1上升到圆柱的最高点,
m1与m2组成的系统减少的势能为:
(2分)
(3)根据系统机械能守恒:![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341939517.gif)
(2分)
(2分)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341892784.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341845405.gif)
(2)两球从静止开始至m1上升到圆柱的最高点,
m1与m2组成的系统减少的势能为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241223418611135.gif)
(3)根据系统机械能守恒:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341939517.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241223419541099.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122341876592.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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