题目内容
如图10在光滑水平面上叠放AB两物体,其间有摩擦,mA=2 kg,mB=1 kg,速度的大小均为v0=10 m/s,设A板足够长,当观察到B做加速运动时,A的可能速度为( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241243331881231.png)
A.2 m/s | B.3 m/s |
C.4 m/s | D.5 m/s |
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241243331881231.png)
C
在摩擦力的作用下,因为B物体质量下,所以B物体先做减速运动,后来有反向做加速运动,A一直做减速运动,最终当两物体速度相等时,一起匀速设最终速度为v,根据系统动量守恒有:
,解得
,则A的速度大于![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333578648.png)
设B的速度为零时,A的速度为
,则有
,解得
,可知A的速度小于
,综合可知A的速度可能为![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333718495.png)
故选C
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333531866.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333547719.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333578648.png)
设B的速度为零时,A的速度为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333593308.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333656789.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333671584.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333703491.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124333718495.png)
故选C
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目