题目内容
内侧轨道为1/4圆周的小车的质量为M,半径为R,一个质量为m的物体从小车的顶点由静止滑下,物体滑离小车底端时的速度设为
,不计一切摩擦,下列说法中正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241548051981038.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154805120262.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241548051981038.png)
A.物体滑离小车时的速度![]() |
B.物块滑离小车时的速度![]() |
C.物块滑离小车时小车的速度![]() |
D.物块滑离小车时小车的速度![]() |
BC
试题分析:将小车和小球看做一个整体,小球滑动过程中,整体动量守恒,初动量为零,所以有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154805853720.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154805588715.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154806275785.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154805261583.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154805510608.png)
点评:本题的关键是明白小车固定和小车自由移动两种情况下的不同点,是一道经典的题目,
![](http://thumb2018.1010pic.com/images/loading.gif)
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