题目内容
(9分)如图所示,被压缩后锁定的弹簧一端固定在墙上,另一端与质量为2m的物体A相连接,光滑的水平面和光滑的曲面平滑相连。有一质量为m的物体B,从高h处由静止开始沿光滑曲面滑下,与物体A相碰,碰后两物体立即以相同速度向右运动(但两个物体不粘连),同时弹簧的锁定被解除,返回时物体B能上升的最大高度为
,试求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241424187912562.png)
①碰撞结束瞬间AB的共同速度v1。
②弹簧锁定时对应的弹性势能EP。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142418729408.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241424187912562.png)
①碰撞结束瞬间AB的共同速度v1。
②弹簧锁定时对应的弹性势能EP。
①
②![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142419228748.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142418932660.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142419228748.png)
①B从高h处滑到平面时的速度为v0,由动能定理有
,
(2分)
A与B碰后共速为v1,由动量守恒有
,
(2分)
②B返回时离开A的速度为
,有
(1分)
对A、B和弹簧有
(2分)
(2分)本题考查的是动能定理和动量守恒结合的问题。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142419306753.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142419462569.png)
A与B碰后共速为v1,由动量守恒有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142419524645.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142418932660.png)
②B返回时离开A的速度为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142419930332.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142420086788.png)
对A、B和弹簧有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142420164869.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824142419228748.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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