题目内容
将一小球竖直上抛,若小球在第3秒内的位移是零,再过3秒钟小球落至地面。则小球抛出点离地面的高度是( )(不计空气阻力,g = 10m/s2)
A.61.25m | B.31.25m | C.30m | D.20m |
C
试题分析:由于小球在第3秒内的位移是零,第3秒的平均速度也为零,而平均速度等于中间时刻的速度,即第
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000008203412.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000008203412.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000008359412.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250000083751299.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250000083901346.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000008406696.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.61.25m | B.31.25m | C.30m | D.20m |