题目内容
如图所示,用同样材料做成的A、B、c三个物体放在匀速转动的水平转台上随转台一起绕竖直轴转动.已知三物体质量间的关系ma=2mb=3mc,转动半径之间的关系是rC=2rA=2rB,那么以下说法中错误的是:( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241251276784822.png)
A.物体A受到的摩擦力最大
B.物体B受到的摩擦力最小
C.物体C的向心加速度最大
D.转台转速加快时,物体B最先开始滑动
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241251276784822.png)
A.物体A受到的摩擦力最大
B.物体B受到的摩擦力最小
C.物体C的向心加速度最大
D.转台转速加快时,物体B最先开始滑动
D
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AB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C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D错
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824125127694359.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241251277251331.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241251277411305.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824125127756827.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241251279281071.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241251279441072.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824125127975698.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824125127990346.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824125128084854.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241251281001539.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241251281311531.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824125128146900.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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