题目内容
如图所示,物块A的质量为
、物块B的质量为
,开始都静止在光滑水平面上,现用大小均为F=5N的两个力分别作A和B上,使A、B沿一条直线相向运动,物块A上的力作用时间为
,物块B上的力作用时问为
,先后撤去这两个力后两物块发生对心正碰。如果碰撞后两个物块粘合为一体,求其运动的速度。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250047071752614.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707113633.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707128621.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707144458.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707159478.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250047071752614.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707191356.png)
试题分析:对物块A由动量定理有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707222652.png)
对物块B由动量定理有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707237673.png)
设撤去外力F后A、B碰撞并粘合在一起的共同速度大小为v,规定向左为运动的正方向,
由动量守恒定律有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707253872.png)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250047072841548.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004707300381.png)
方向向左 (1分)
![](http://thumb2018.1010pic.com/images/loading.gif)
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