题目内容
质量为lkg的物体,放在动摩擦因数为0.2的水平面上,在水平拉力的作用下由静止开始运动,水平拉力做的功W和物体发生的位移X之间的关系如图所示,重力加速度为10m/s2,则下列说法正确的是:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082413245714912980.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082413245714912980.png)
A.s=3m时速度大小为![]() |
B.s=9m时速度大小为![]() |
C.OA段加速度大小为3m/s2 |
D.AB段加速度大小为2m/s2 |
AC
S=3m时F力做功15J,则力F=W/S=5N,则OA段的加速度
,可解得a=3m/s2,则D错C正确;由速度位移公式
,可得
,A正确;从静止开始到s=9m整个过程运用动能定理有:
,且
,
,代入数据得
,故B错误;答案为AC。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324572891189.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132457321725.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132457414926.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324574771151.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324575081083.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132457539714.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132457601941.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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