题目内容
(12分)雨后,屋檐还在不断滴着水滴,如图所示。小红认真观察后发现,这些水滴都是在质量积累到足够大时才由静止开始下落。她测得,屋檐到窗台的距离H = 3.2m,窗户的高度为h = 1.4m。如果g取10m/s2,试计算:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250009180113047.png)
(1)水滴下落到达窗台时的速度大小;
(2)水滴经过窗户的时间。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250009180113047.png)
(1)水滴下落到达窗台时的速度大小;
(2)水滴经过窗户的时间。
(1)8 m/s(2)0.2s
试题分析:(1)水滴下落至窗台通过的距离为 H =" 3.2" m,水滴做自由落体运动
由
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000918026580.png)
得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000918042916.png)
(2)设水滴下落至窗户上边缘的时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000918057291.png)
由
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000918167747.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250009181671702.png)
设水滴下落至窗台的时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000918260327.png)
由
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000918276662.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250009182911267.png)
水滴经过窗户的时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000918307954.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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