题目内容
如图,传送带的水平部分长为L,向右传动速率为v ,在其左端无初速释放一小木块,若木块与传送带间的动摩擦因数为μ,则木块从左端运动到右端的时间可能是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241538539091968.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241538539091968.jpg)
A.![]() | B.![]() |
C.![]() | D.![]() |
ACD
试题分析:木块在传送带上的加速度为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153854252751.png)
木块在传送带上运动有两种可能:
(1) 物块一直匀加速到右端,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153854424619.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153854595702.png)
若到右端时速度刚好为v,则有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153854798820.png)
(2)木块先匀加速到与传送带同速后,再匀速到右端匀加速阶段所用时间
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153854860568.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241538549231293.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153855172866.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153855282957.png)
点评:本题的难度较大,很容易出错,原因就是对小物体在传送带上的运动过程不能准确的分析出来,
![](http://thumb2018.1010pic.com/images/loading.gif)
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