题目内容
(如图5所示,质量为m的等边三棱柱静止在水平放置的斜面上.已知三棱柱与斜面之间的动擦因数为μ,斜面的倾角为30°,则斜面对三棱柱的支持力与摩擦力的大小分别为 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241414183932566.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241414183932566.jpg)
A.![]() ![]() | B.![]() ![]() |
C.![]() ![]() | D.![]() ![]() |
A
三棱柱受到重力、支持力和摩擦力三个力的作用而平衡,故FN=mgcos30°=
mg,Ff=mgsinθ=
mg,A正确.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141418409453.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141418471338.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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