题目内容
汽车在水平路面上从静开始做匀加速直线运动,到t1末关闭发动机在地面摩擦力的作用下做匀减速直线运动,到t2末静止。其v-t图像如图所示,图中
。在整个过程中,若汽车牵引力F的平均功率为P1;汽车克服摩擦力f的平均功率为P2,汽车的阻力仅考虑摩擦力,则下列结论正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025124362635.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512420437.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025124362635.jpg)
A.P1<P2 | B.![]() | C.F>2f | D.F<2f |
BD
试题分析:汽车整个过程中牵引力做正功,摩擦力做负功,从静止到静止,所以根据动能定理可得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512483611.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512498426.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512467449.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512529622.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512561554.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512420437.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512592441.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512607472.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002512639491.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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