题目内容
一个质量为1.0kg的小球从1/4园弧AB的上端A点自由下滑,圆弧的半径R=0.2m,小球以2m/s的速度从B点水平抛出,B点离地高度1.25m,忽略空气阻力的影响,求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241326440406853.png)
(1) 小球经过B点时,受到B点对它的支持力
(2) 小球落点C到B点的水平距离x
(3) 小球落到C点时的速度![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644103316.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241326440406853.png)
(1) 小球经过B点时,受到B点对它的支持力
(2) 小球落点C到B点的水平距离x
(3) 小球落到C点时的速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644103316.png)
(1)30N (2)1m (3)
速度与水平方向的夹角
满足![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644212636.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644165622.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644196310.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644212636.png)
(1)B点:
,N=30N;
(2)竖直方向有:
,![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644384456.png)
水平距离![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644430574.png)
(3)C点的竖直速度
,则
,方向与水平方向的夹角满足:![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644555812.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644274858.png)
(2)竖直方向有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644321654.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644384456.png)
水平距离
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644430574.png)
(3)C点的竖直速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644477741.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644508975.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132644555812.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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