题目内容
如图所示,从某高度水平抛出一小球,经过时间t到达地面时,速度与水平方向的夹角为θ,不计空气阻力,重力加速度为g.下列说法正确的是( ).
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250037143892015.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250037143892015.png)
A.小球水平抛出时的初速度大小为gttan θ |
B.小球在t时间内的位移方向与水平方向的夹角为![]() |
C.若小球初速度增大,则平抛运动的时间变长 |
D.若小球初速度增大,则θ减小 |
D
试题分析:解决本题的关键掌握平抛运动的处理方法,在水平方向做匀速直线运动,在竖直方向做自由落体运动.
速度与水平方向夹角的正切值
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003714421873.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003714436438.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003714421873.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250037144831299.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003714499662.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003714514584.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003714530672.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003714545511.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003714577790.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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