题目内容
汽车以10 m/s的速度在平直公路上匀速行驶,刹车后经2 s速度变为6 m/s,求:
(1)刹车后2 s内前进的距离及刹车过程中的加速度大小;
(2)刹车后前进9 m所用的时间;
(3)刹车后8 s内前进的距离.
(1)刹车后2 s内前进的距离及刹车过程中的加速度大小;
(2)刹车后前进9 m所用的时间;
(3)刹车后8 s内前进的距离.
(1)16 m 2 m/s2 (2)1 s (3)25 m
试题分析:(1)汽车刹车后做匀减速运动,由
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842771597.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842787564.png)
由位移公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842818769.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842833892.png)
(本题也可由平均速度公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842849802.png)
(2)由位移公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842818769.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842896609.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842911481.png)
(3)设汽车刹车所用最长时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842943267.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842943267.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842974527.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002842943267.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002843005168.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250028430361442.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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