题目内容
如图为湖边一倾角为30°的大坝的横截面示意图,水面与大坝的交点为O。一人站在A点处以速度v0沿水平方向扔小石子,已知AO=40m,g取10m/s2。下列说法正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242327577932893.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242327577932893.png)
A.若v0=18m/s,则石块可以落入水中 |
B.若石块能落入水中,则v0越大,落水时速度方向与水平面的夹角越大 |
C.若石块不能落入水中,则v0越大,落到斜面上时速度方向与斜面的夹角越大 |
D.若石块不能落入水中,则v0越大,落到斜面上时速度方向与斜面的夹角越小 |
A
试题分析:若石块恰能落到O点,,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824232759057728.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824232800211893.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824232801756310.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242328031751006.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824232801756310.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824232801756310.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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