题目内容
如图所示,小球沿斜面向上运动, 依次经a、b、c、d到达最高点e.已知ab="bd=8m,"
bc=2m,小球从a到c和从c到d所用的时间都是2s, 则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250010359642587.png)
bc=2m,小球从a到c和从c到d所用的时间都是2s, 则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250010359642587.png)
A.a=-1m/s2 |
B.vc=4m/s |
C.de=2m |
D.从d到e所用时间为3s |
ABC
试题分析:c到d和a到c的位移差为-4m,根据Δx=aT2可求加速度a=-1m/s2,A正确;设时间间隔T=2s,C点是ad过程的中间时刻,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001036011940.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001036042575.png)
则de=2m,C正确;根据
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001036057527.png)
可求d点的速度vd =2m/s,可求从d到e所用的时间为2s,D错误。
![](http://thumb2018.1010pic.com/images/loading.gif)
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