题目内容
质量为m1=4kg、m2=2kg的A、B两球,在光滑的水平面上相向运动,若A球的速度为v1=3m/s,B球的速度为v2=-3m/s,发生正碰后,两球的速度分别变为v1'和v2',则v1'和v2'可能为 ( )
A.v1'=1m/s,v2'=1m/s B.v1'=4m/s,v2'=-5m/s
C.v1'=2m/s,v2'=-1m/s D.v1'=-1m/s,v2'=5m/s
A.v1'=1m/s,v2'=1m/s B.v1'=4m/s,v2'=-5m/s
C.v1'=2m/s,v2'=-1m/s D.v1'=-1m/s,v2'=5m/s
AD
试题分析:碰撞前两物体的总动量为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824180128714897.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824180128964600.png)
碰撞后要满足
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824180129260435.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824180129510556.png)
A中满足
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241801297911048.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824180130087681.png)
B中
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824180130337727.png)
C中正碰后B的运动方向没有变化,所以C不符合题意,C错误
D中满足
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824180129260435.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824180129510556.png)
故选AD
点评:对于碰撞过程要遵守三大规律:1、是动量守恒定律;2、总动能不增加;3、符合物体的实际运动情况
![](http://thumb2018.1010pic.com/images/loading.gif)
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