题目内容
如图所示,在高为
的平台边缘水平抛出小球A,同时在水平地面上距台面边缘水平距离为
处竖直上抛小球B,两球运动轨迹在同一竖直平面内,不计空气阻力,重力加速度为
,若两球能在空中相遇,则小球A的初速度
应大于
,A、B两球初速度之比为 。(
)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241236516125129.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651472619.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651503556.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651518278.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651550356.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651565455.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651581683.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241236516125129.png)
0.5 ; 1/2
平抛运动,
,
,计算可得t<0.2s,所以小球A的初速度
应大于0.5
,A、B两球初速度之比为s:h=1:2
故答案为:0.5 1:2
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651643465.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651659926.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651550356.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123651565455.png)
故答案为:0.5 1:2
![](http://thumb2018.1010pic.com/images/loading.gif)
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