题目内容
如右图所示,A?B?C三个物体放在旋转平台上,动摩擦因数均为μ,已知A的质量为2m,B?C的质量均为m,A?B离轴距离均为R, C距离轴为2R,则当圆台旋转时
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241353329492816.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241353329492816.png)
A.C物体的向心加速度最大 |
B.B物体的摩擦力最小 |
C.当圆台转速增加时, A比C先滑动 |
D.当圆台转速增加时, B比A先滑动 |
AB
A、B、C三物体随平台做匀速圆周运动,角速度相等,设都为
,其向心力是由所受的静摩擦力提供,由向心力公式可得三物体受到的静摩擦力分别为
,
,
所以B正确。三物体的向心加速度分别为
,
,
可得C的向心加速度最大,所以A正确。假设三个物体滑动,摩擦力变为动摩擦力,材料一样所以动摩擦因数一样,设为
,由公式
得三个物体滑动时的分别要达到的角速度为
,
,
,c物体最小,当转台转速加快时,C物体最先开始滑动,故CD错
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135333152308.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241353331991056.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241353332141024.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135333261709.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135333324862.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135333402856.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135333448597.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135333495301.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135333526724.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241353337451089.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241353337761084.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135333823710.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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