题目内容
如图所示,半径为R的半圆光滑轨道固定在水平地面上。A、B点在同一竖直直线上。质量为
的小球以某一速度从C点运动到A点进入轨道,小球与水平地面间的动摩擦因数为
。它经过最高点B飞出后又能落回到C点,AC=2R。求小球从C点开始运动时的初速度v0的大小。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242243354154728.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824224333402337.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824224334775301.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242243354154728.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824224335602841.png)
试题分析:小球从C点运动到A点,摩擦力做负功,根据动能定理有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242243368661097.png)
小球从A点做圆周运动运动到B,根据机械能守恒定律有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242243380511059.png)
小球从B平抛落到C点,根据平抛运动的规律有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824224338894581.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824224339752675.png)
联系以上各式,解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824224335602841.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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