题目内容
如图所示,某人从高出水平地面h的坡上水平击出一个高尔夫球 (可视为质点)。由于恒定的水平风力的作用,球恰好竖直落入距击出点水平距离为L的A穴,则该球从被击出到刚落入A穴的时间t= ____________,球被击出时的速度大小
= ________________。(结果用h、L和重力加速度g表示)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241319573176743.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957285332.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241319573176743.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957348587.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957379666.png)
球水平击出后,竖直方向做自由落体运动,由
得:球的运动时间
,水平方向由于恒定的风力作用球做匀减速直线运动,竖直落入A穴,说明水平方向速度减为零。水平方向平均速度
=
,水平方向位移L=
t,将前面t和
表达式代入得:
=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957379666.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957410650.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957441675.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957457270.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957488532.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957457270.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957457270.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957285332.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824131957379666.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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