题目内容
(多选题)在光滑水平面上,一质量为m、速度大小为v的A球与质量为2m静止的B球碰撞发生正碰,碰撞可能是弹性的,也可能是非弹性的。则碰后B球的速度大小可能是( )
A.0.6v | B.0.4v | C.0.3v | D.0.2v |
AB
试题分析:若vB=0.6v,规定A球初速度方向为正方向,由动量守恒得:mv=mvA+2m?0.6v,
得vA=-0.2v,碰撞前系统的总动能为Ek=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004244907338.png)
碰撞后系统的总动能为Ek′=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004244907338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004244907338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004244907338.png)
B、若vB=0.4v,规定A球初速度方向为正方向,
由动量守恒得:mv=mvA+2m?0.4v,得vA=0.2v,
碰撞后系统的总动能为Ek′=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004244907338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004244907338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004244907338.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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