题目内容
如右图所示,一质量为m的物体恰能在质量为M的斜劈上匀速下滑,斜劈保持静止.现用一沿斜面向下的外力F推此物体,使物体加速下滑,设此过程中斜劈受到地面的摩擦力为Ff,支持力为FN.则下列说法正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242150226982651.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242150226982651.jpg)
A.![]() ![]() |
B.![]() ![]() |
C.![]() ![]() |
D.![]() ![]() |
A
试题分析:当m在M上匀速下滑时,m对M的作用力
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824215031746548.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824215033212480.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824215031746548.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824215035178272.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824215024258835.png)
故选A
点评:做此类型问题受力分析是关键,结合平衡条件分析,基础题,比较简单
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.![]() ![]() |
B.![]() ![]() |
C.![]() ![]() |
D.![]() ![]() |