题目内容
(15分)某兴趣小组对一辆自制遥控小车的性能进行研究。他们让这辆小车在水平的直轨道上由静止开始运动,并将小车运动的全过程记录下来,通过处理转化为v—t图象,如图所示(除2s—10s时间段图象为曲线外,其余时间段图象均为直线)。已知在小车运动的过程中,2s—14s时间段内小车的功率保持不变,在14s末停止遥控而让小车自由滑行,小车的质量为1.0kg,可认为在整个运动过程中小车所受到的阻力大小不变。求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307136494.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250023071685256.png)
(1)小车所受到的阻力大小;
(2)小车匀速行驶阶段的功率;
(3)小车在加速运动过程中位移的大小。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307136494.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250023071685256.png)
(1)小车所受到的阻力大小;
(2)小车匀速行驶阶段的功率;
(3)小车在加速运动过程中位移的大小。
(1)f=1.5N (2)P=9w (3)S=42m
试题分析:(1)在14s末停止遥控而让小车自由滑行,由图象可得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307199641.png)
小车所受到的阻力:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307214463.png)
(2)小车匀速行驶,
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307230443.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307246464.png)
(3)0s—2s小车位移:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307261463.png)
2s—10s小车位移为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307277285.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307292492.png)
所以
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307308412.png)
小车在加速运动过程中位移的大小:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002307324536.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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