题目内容
如图所示,质量为m的物体在与水平方向成θ角的拉力作用下,在水平面上匀速移动位移s.已知物体与平向间的动摩擦因数为μ,则拉力做功大小为 ( ).
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324380552172.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324380552172.png)
A.μmgs | B.μmgscosθ | C.![]() | D.![]() |
D
匀速运动,则物体受重力、支持力、水平向左的摩擦力和F四力作用而平衡,则水平方向上
,解得
,则拉力做功为
。答案为D。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324381791188.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324382111284.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324382731698.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.μmgs | B.μmgscosθ | C.![]() | D.![]() |