题目内容
如图所示,跨在光滑圆柱体侧面上的轻绳两端分别系有质量为 mA、mB的小球,系统处于静止状态.A、B小球与圆心的连线分别与水平面成60°和30°角,则两球的质量之比mA:mB和剪断轻绳时两球的加速度之比aA:aB分别为 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241435094372533.jpg)
A.1:1 1:2 B.1:1 1:
C.
:1 1:1 D.
:1 1:![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143509453337.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241435094372533.jpg)
A.1:1 1:2 B.1:1 1:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143509453337.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143509453337.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143509453337.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143509453337.png)
D
分析A、B两小球的受力情况,由平衡条件可得:FA=mAgcos60°,FB=mBgcos30°,由FA=FB可得:mA∶mB=
∶1.剪断轻绳时,两球的合力均为小球重力沿圆柱体面切向的分力,由牛顿第二定律可得:mAgcos60°=mAaA,mBgcos30°=mBaB,求得:aA=gcos60°,aB=gcos30°,aA∶aB=1∶
,故只有D正确
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143509453337.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143509453337.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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