题目内容
一只质量为2kg的小球,从距水平地面5m高的点以10m/s的初速度水平抛出.不计空气阻力,取重力加速度g=10m/s2.求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250018377404821.jpg)
(1)小球刚抛出时相对于水平地面的重力势能;
(2)小球在空中飞行的时间;
(3)小球抛出的水平距离.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250018377404821.jpg)
(1)小球刚抛出时相对于水平地面的重力势能;
(2)小球在空中飞行的时间;
(3)小球抛出的水平距离.
(1)100J(2)
(3)![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837771515.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837755378.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837771515.png)
试题分析:
(1)根据
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837786681.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250018378021045.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837818650.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837833675.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837755378.png)
(3)小球在水平方向上做匀速直线运动,故根据
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837864492.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001837771515.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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