题目内容
质量为
kg的汽车从静止沿平直公路启动的速度与时间图像如图所示,A点表示匀加速的最后时刻,B点表示汽车达到最大速度,设汽车受恒定阻力,g=10m/s2,则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241945246076279.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194524139486.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241945246076279.jpg)
A.匀加速的加速度大小是0.5m/s |
B.阻力大小是![]() |
C.汽车的额定功率为![]() |
D.汽车从静止到达到最大速度时的总路程是337.5m |
D
试题分析:OA阶段表示匀加速直线运动,斜率表示加速度,故
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194526728950.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194527368540.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194528008874.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194528975555.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194529536693.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194529864671.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194530145830.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824194530426615.png)
故选D
点评:汽车做恒定牵引力启动,先做匀加速直线运动,当功率达到额定功率后,牵引力开始减小,做变加速直线运动,当牵引力等于阻力时,速度最大,做匀速直线运动,,
![](http://thumb2018.1010pic.com/images/loading.gif)
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