题目内容
如图所示,光滑斜面AE被分成四个相等的部分,一物体由A点从静止释放做匀加速直线运动,下列结论不正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514499232914.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514499232914.png)
A.物体到达各点的速率之比 vB:vC:vD:vE=1:![]() ![]() |
B.物体到达各点经历的时间tE=2tB=![]() ![]() |
C.物体从A到E的平均速度v=vB |
D.物体通过每一部分时,其速度增量vB-vA=vC-vB=vD-vC=vE-vD |
D
试题分析:根据运动学公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151450579662.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151450657577.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241514507811358.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151450844907.png)
根据运动学公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151450906773.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151450969628.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151451015915.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151451265980.png)
由于
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151451312518.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151451374705.png)
因为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151450844907.png)
因为题中让选错误的,所以选D
点评:本题对运动学公式要求较高,要求学生对所有的运动学公式不仅要熟悉而且要熟练,要灵活,基本方法就是平时多练并且尽可能尝试一题多解.
![](http://thumb2018.1010pic.com/images/loading.gif)
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