题目内容
一质点沿直线Ox方向做变速运动,它离开O点的距离x随时间t变化的关系为
x=(5+2t3) m,它的速度随时间t变化的关系为v=6t2 m/s,该质点在t=0到
t=2 s间的平均速度和t=2 s到t=3 s间的平均速度的大小分别为( )
x=(5+2t3) m,它的速度随时间t变化的关系为v=6t2 m/s,该质点在t=0到
t=2 s间的平均速度和t=2 s到t=3 s间的平均速度的大小分别为( )
A.12 m/s 39 m/s |
B.8 m/s 38 m/s |
C.12 m/s 19.5 m/s |
D.8 m/s 13 m/s |
B
试题分析:根据离开O点的距离随时间变化的关系
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752242655.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752257363.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752273421.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752304378.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752320471.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752335374.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752351500.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752257363.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752304378.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752429886.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752304378.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752335374.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000752476923.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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