题目内容
如图,物体A的质量为2m,物体B的质量为m,A与地面间的动摩擦因数为μ,B与地面间的摩擦不计,用水平力F向右推A使A、B一起加速运动,则B对A的作用力大小为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241321425231025.png)
A.
B.![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132142617838.png)
C.
D.![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132142679886.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241321425231025.png)
A.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132142570778.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132142617838.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132142648808.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132142679886.png)
B
整体法:整体受到向右的推力F,向左的滑动摩擦力
,则根据牛顿第二运动定律可得整体的加速度大小为
,隔离法:分析B,受到A对B的向右的推力,即
,A对B的作用力和B对A的作用力是一对相互作用力,所以B对A的作用力为
,B正确。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132142726639.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132142757859.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241321427881054.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132143007763.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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