题目内容
让滑块沿倾斜的气垫导轨由静止开始做加速下滑,滑块上有一块很窄的挡光片,在它通过的路径中取AE并分成相等的四段,如图1-2-17所示,
表示B点的瞬时速度,
表示AE段的平均速度,则
和
的关系是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241135436561933.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543375213.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543390199.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543375213.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543390199.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241135436561933.gif)
A.![]() ![]() |
B.![]() ![]() |
C.![]() ![]() |
D.以上三个关系都有可能 |
C
如果挡光片是从A位置开始下滑的,则B位置对应挡光片经过AE段的中间时刻,则有
=
,但此题中的挡光片是A的上侧滑下后经过A位置的,所以选项A肯定不正确;设A、B间的距离为
,则
,![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543999546.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543375213.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543390199.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543968192.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543983498.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113543999546.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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