题目内容
质量为1kg的小球在空中自由下落,与水平地面相碰后立即被反弹,之后又上升到某一高度处。此过程中小球的速度随时间变化规律的图像如图所示。不计空气阻力,g取10m/s
。下列说法中正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242208203473831.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824220819521242.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242208203473831.jpg)
A.小球在下落过程中重力做功12.5J |
B.小球在上升过程中重力势能增加8J |
C.小球与地面接触过程中机械能损失8J |
D.小球刚与地面接触时重力的瞬时功率为50w |
ACD
试题分析:v---t图像与时间轴所围成的面积代表位移,0到0.5s为下降过程, 下降高度
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824220820784971.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824220821829842.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242208229991041.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824220824232721.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824220825651971.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824220826587968.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242208280691237.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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