题目内容
如图所示,A、B两物体相距x="10" m,物体A以
="2" m/s的速度向右匀速运动,而物体B此时的速度
="6" m/s,只在摩擦阻力作用下向右做匀减速运动,加速度大小为a=1
,那么物体A追上物体B所用的时间为( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241517234127289.png)
A.10 s
B.12 s
C.13 s
D.14 s
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151723116356.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151723194356.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151723350497.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241517234127289.png)
A.10 s
B.12 s
C.13 s
D.14 s
D
试题分析:物体A做匀速直线运动,位移为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151723506630.png)
物体B做匀减速直线运动,位移为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241517235991101.png)
当物体乙的速度为零时时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151723708294.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151723755541.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151723880620.png)
在
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151723942461.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241517239891010.png)
点评:特别要注意物体B做匀减速运动,要分清是减速过程追上还是静止后被追上;第二种情况下的位移用位移时间公式求解时要注意时间是减速的时间,而不是总时间.
![](http://thumb2018.1010pic.com/images/loading.gif)
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