题目内容
某兴趣小组遥控一辆玩具车,使其在水平路面上由静止启动,在前2 s内做匀加速直线运动,2 s末达到额定功率,2s到14s保持额定功率运动,14s末停止遥控,让玩具车自由滑行,其v-t图象如图所示。可认为整个过程玩具车所受阻力大小不变,已知玩具车的质量为m=1kg,(取g="10" m/s2),则 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250043412232439.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250043412232439.png)
A.玩具车所受阻力大小为2N | B.玩具车在4s末牵引力的瞬时功率为9w |
C.玩具车在2到10秒内位移的大小为39m | D.玩具车整个过程的位移为90m |
BC
试题分析:由图像可知在14s后做匀减速直线运动,加速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004341255959.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004341270775.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004341286898.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004341301763.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004341333818.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250043413481167.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004341364553.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250043413791307.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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