题目内容
一物体由静止开始沿足够长斜面向下匀加速直线运动,已知它在第一个2s内的位移是3m,则它在第四个2s内的位移大小是
A.21m | B.14m | C.48m | D.36m |
A
由前两秒位移为3可知:
,![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130549127653.png)
根据匀变速直线运动相邻相同时间内位移差为常数:
,
3×1.5×4=21m.A对。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130549112625.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130549127653.png)
根据匀变速直线运动相邻相同时间内位移差为常数:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130549159555.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130549377689.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.21m | B.14m | C.48m | D.36m |