题目内容
(8分)如图所示,在倾角为θ的光滑斜面上,放一个重为G的光滑小球,并用竖直挡板挡住.求挡板和斜面对小球的作用力的大小和方向。![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241153224292619.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241153224292619.jpg)
Gtanθ,水平向右;
,垂直于斜面向上
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115322445332.gif)
挡板对小球的作用力F1方向水平向右,斜面对小球的作用力F2方向垂直于斜面向上.小球处于静止状态,合力为零,G与F1的合力与F2的大小相等、方向相反,如图所示,则F2cosθ=G,F2sinθ=F1
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241153224613068.jpg)
解得F1=Gtanθ,F2=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115322445332.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241153224613068.jpg)
解得F1=Gtanθ,F2=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115322445332.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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