题目内容
如图,表面光滑的固定斜面顶端安装一定滑轮,小物块A、B用轻绳连接并跨过滑轮(不计滑轮的质量和摩擦)。初始时刻,A、B处于同一高度并恰好静止状态。剪断轻绳后A下落、B沿斜面下滑,则从剪断轻绳到物块着地,两物块
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435387669.png)
A.速率的变化量不同
B.机械能的变化量不同
C.重力势能的变化量相同
D.重力做功的平均功率相同
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435387669.png)
A.速率的变化量不同
B.机械能的变化量不同
C.重力势能的变化量相同
D.重力做功的平均功率相同
D
试题分析:剪断轻绳后,A做自由落体运动,B沿斜面做初速度为零的匀加速直线运动,只有重力对两物块做功,根据机械能守恒定律得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435449811.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435465623.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435496793.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435511769.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435527532.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435558756.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435574760.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250044355891160.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435605353.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435636985.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435777983.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250044357921368.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004435511769.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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