题目内容
一矿井深125m,在井口每隔一段时间释放一个小球,当第11个小球刚从井口开始下落时第1个球恰好到达井底。则:
(1)相邻的两个小球下落的时间间隔是 s;
(2)这时第3个小球跟第5个小球相距 m。(g取10 m/s2)
(1)相邻的两个小球下落的时间间隔是 s;
(2)这时第3个小球跟第5个小球相距 m。(g取10 m/s2)
0.5 35
试题分析:(1)设小球自由下落到达井底经历时间为t,则由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824162819802650.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824162820036783.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824162820348707.png)
(2)第一个小球恰好到达井底时,第三个球已下降4s,第五个球已下降3s,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241628206911064.png)
点评:根据
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824162819802650.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824162821018751.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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