题目内容
如图所示,竖直平面内的3/4圆弧形光滑管道半径略大于小球半径,管道中
心到圆心距离为R,A端与圆心O等高,AD为水平面,B端在O的正下方,小球自A点正上方由静止释放,自由下落至A点进入管道,当小球到达B点时,管壁对小球的弹力大小为小球重力的9倍.求:
(1)释放点距A的竖直高度;
(2)落点C与A的水平距离![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241221386674041.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082412213851165.gif)
(1)释放点距A的竖直高度;
(2)落点C与A的水平距离
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241221386674041.jpg)
(1)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138683378.gif)
(2)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138698577.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138683378.gif)
(2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138698577.gif)
(1)设小球到达B点的速度为
,因为到达B点时管壁对小球的弹力大小为小球重力大小的9倍,所以有
又由机械能守恒定律得
∴![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138776268.gif)
(2)设小球到达最高点的速度为
,落点C与A的水平距离为![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138808209.gif)
由机械能守恒定律得![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138870515.gif)
由平抛运动规律得![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138886336.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138979304.gif)
由此可解得![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138995361.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138730200.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138745432.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138761459.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138776268.gif)
(2)设小球到达最高点的速度为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138792225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138808209.gif)
由机械能守恒定律得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138870515.gif)
由平抛运动规律得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138886336.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138979304.gif)
由此可解得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122138995361.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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