题目内容
重150N的光滑球A悬空靠在墙和木板B之间,木板B的重力为1500N,且静止在水平地板上,如图所示,求:
小题1:墙和木块B所受压力各为多少?
小题2:水平地板所受的压力和木块B所受的摩擦力各为多少?![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241147456722129.png)
小题1:墙和木块B所受压力各为多少?
小题2:水平地板所受的压力和木块B所受的摩擦力各为多少?
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241147456722129.png)
小题1:N2=150
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745687341.png)
小题2:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745718677.png)
小题1:
小球A和木块B受力分析如图所示,
用N1、N2、N3、N1分别表示木块对A的弹
力、墙壁对A的支持力、地面对木块的支持
力和小球对木块的弹力。
对小球A:N1sin60°= N2 ①
N1cos60°= GA ②
由以上两式得N2=150
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745687341.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241147457814971.png)
小题2:根据作用力和反作用力,墙壁受到的压力
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745796725.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745828589.png)
对木块B:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745843925.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745874780.png)
把
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745828589.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745921606.png)
根据作用力和反作用力的关系,水平地板所受的压力
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114745718677.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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