题目内容
如图甲所示,静止在水平地面的物块A,受到水平向右的拉力F作用,F与时间t的关系如图乙所示,设物块与地面的静摩擦力最大值fm与滑动摩擦力大小相等,则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163106503955.png)
甲 乙
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163106503955.png)
甲 乙
A.0~t1时间内F的功率逐渐增大 | B.t2时刻物块A的加速度最大 |
C.t2时刻后物块A做反向运动 | D.t3时刻物块A的动能最大 |
BD
试题分析:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163106831291.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163106831291.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163107564327.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163107767327.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163106831291.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163107564327.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163107564327.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163107564327.png)
故选AD
点评:目前已知的所有宏观物体都是靠惯性运动,力只是改变速度的原因,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163106831291.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163106831291.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163107564327.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163107564327.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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