题目内容
如图,质量为m的物体放在倾角为θ的斜面上,物体与斜面均粗糙。在水平恒力F的作用下,物体沿斜面向上匀速运动,
求(1)物体所受的摩擦力和支持力;
(2)物体与斜面间的动摩擦因数。![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514308291323.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151430891187.png)
求(1)物体所受的摩擦力和支持力;
(2)物体与斜面间的动摩擦因数。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514308291323.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151430891187.png)
(1)
(2)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514310631140.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151430954910.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151431001949.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514310631140.png)
试题分析:(1)对物体进行受力分析如图,沿斜面方向有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151431125949.png)
所以
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151430954910.png)
垂直斜面方向有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151431375973.png)
所以
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151431001949.png)
(2)滑动摩擦力
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151431500597.png)
联立①②③解得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514310631140.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514316403480.jpg)
点评:在分析受力时,用正交分解法有时比较简单,本题虽然没有画出坐标轴,但是用的却是正交分解法。
![](http://thumb2018.1010pic.com/images/loading.gif)
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