题目内容
将小球从如图所示的阶梯状平台上以4 m/s的速度水平抛出,所有台阶的高度和宽度均为1.0 m,取g=10 m/s2,小球抛出后首先落到的台阶是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241304126102944.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241304126102944.png)
A.第一级台阶 | B.第二级台阶 |
C.第三级台阶 | D.第四级台阶 |
D
竖直方向有:![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130412657713.png)
运动时间为:![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130412672972.png)
水平距离![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241304127041058.png)
得:n=3.2,所以落在第四节台阶,D对。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130412657713.png)
运动时间为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130412672972.png)
水平距离
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241304127041058.png)
得:n=3.2,所以落在第四节台阶,D对。
![](http://thumb2018.1010pic.com/images/loading.gif)
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