题目内容
如图所示,在光滑水平面上停放着质量为m装有光滑弧形槽的小车,一质量也为m的小球以v0的水平初速度沿槽口向小车滑去,到达某一高度后,小球又返回车右端.则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241141213491961.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241141213491961.jpg)
A.小球以后将向右做平抛运动 |
B.小球将做自由落体运动 |
C.此过程小球对小车做的功为![]() |
D.小球在弧形槽上升的最大高度为![]() |
BC
此过程系统水平方向动量守恒,系统机械能也守恒.小球上升到最高点时,与小车有共同速度v共
则mv0=2mv共,
mv02=
2mv共2+mgh得h=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121427398.gif)
小球回到小车右端有mv0=mv车+mv球
mv02=
mv车2+
mv球2得v车="v0 " v球=0
所以小球做自由落体运动,小球对车做功W=
mv车2=
mv02.
则mv0=2mv共,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121365225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121365225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121427398.gif)
小球回到小车右端有mv0=mv车+mv球
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121365225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121365225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121365225.gif)
所以小球做自由落体运动,小球对车做功W=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121365225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114121365225.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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