题目内容
如图所示,在光滑的水平面上叠放着两木块A、B,质量分别是m1和m2,A、B间的动摩擦因数为μ,若要是把B从A下面拉出来,则拉力的大小至少满足( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401034706.png)
A.
B.![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401065806.png)
C.
D.![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401096645.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401034706.png)
A.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401049818.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401065806.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401080630.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401096645.png)
A
试题分析:要使把B从A下面拉出来,则B要相对于A滑动,所以AB间都是滑动摩擦力,根据牛顿第二定律
对A有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401112828.png)
对B有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401127891.png)
当aB>aA时,能够把B从A下面拉出来,则有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401158867.png)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000401174849.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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