题目内容
如图所示,物体A和B的质量均为
,且分别与跨过定滑轮的轻绳连接(不计绳与滑轮、滑轮与轴之间的摩擦)在用水平变力
拉物体B沿水平方向向右做匀速直线运动的过程中,则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025526062435.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552575337.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552590302.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025526062435.png)
A.物体A也做匀速直线运动 |
B.绳子拉力始终等于物体A所受重力 |
C.绳子对A物体的拉力逐渐增大 |
D.绳子对A物体的拉力逐渐减小 |
D
试题分析:将B物体的速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552637351.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025526538812.png)
则
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552668653.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552684310.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552637351.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552715352.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552731613.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552762534.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552777417.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002552793494.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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