题目内容
光滑水平面上静止的物体,受到一个水平拉力作用开始运动,拉力F随时间t变化如图所示,用
分别表示物体的动能、速度、位移和拉力F的功率,下列四个图象分别定性描述了这些物理量随时间变化的情况,其中正确的是( )![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241138334151076.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241138334314083.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833399437.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241138334151076.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241138334314083.jpg)
BD
由于物体所受的合外力为恒力,物体做匀加速直线运动,其速度
。拉力F的功率
,其
图象,
图象均为过原点的倾斜直线,因而B、D正确;而动能
,位移
,其
图象
图象均不是直线而是抛物线,A、C错误,故选BD。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833462347.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833477456.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833493218.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833524232.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833540694.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833571447.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833571355.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113833587213.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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