题目内容
当前,我国“高铁”事业发展迅猛,假设一辆高速列车在机车牵引力和恒定阻力作用下,在水平轨道上由静止开始启动,其v-t图象如图示,已知在0-t1时段为过原点的倾斜直线,t1时刻达到额定功率P,此后保持功率P不变,在t3时刻达到最大速度v3,以后匀速运动,则下述判断正确的有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241859124824329.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241859124824329.jpg)
A.从![]() ![]() |
B.在t2时刻的加速度大于t1时刻的加速度 |
C.在0至t3时刻,机车的牵引力最大为![]() |
D.该列车所受的恒定阻力大小为![]() |
CD
试题分析:因为从
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824185912497291.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824185913901327.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824185914135557.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824185912997402.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824185914744637.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824185914978659.png)
故选CD
点评:本题的关键是理解机车的启动过程,这道题是以恒定加速度启动,公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824185915290486.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824185915836792.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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