题目内容
如图所示,物体M与m紧靠着置于斜面上,斜面的倾角为
,物体M、m与斜面的动摩擦因数均为
,现施一水平力F作用于M,M和m共同向上加速运动,求它们之间相互作用力的大小。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241151124193304.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112403200.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112419204.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241151124193304.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112450878.gif)
两个物体具有共同的沿斜面向上的加速度,所以可以把它们作为一个整体,其受力如图所示,建立图示坐标系,由牛顿第二定律得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241151124664699.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241151124814140.jpg)
①
②
且
③
为求两个物体之间的相互作用力,把两物体隔离开,对m受力分析如图所示,由牛顿第二定律得
④
⑤
且
⑥
解①~⑥式可得
⑦
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241151124664699.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241151124814140.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112497754.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112512933.gif)
且
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112528408.gif)
为求两个物体之间的相互作用力,把两物体隔离开,对m受力分析如图所示,由牛顿第二定律得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112528564.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112544653.gif)
且
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112559418.gif)
解①~⑥式可得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115112450878.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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