题目内容
如图所示为某质点做直线运动的v-t图象,关于这个质点在4s内的运动情况,下列说法中正确的是:( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250019361303063.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250019361303063.jpg)
A.质点始终向同一方向运动 |
B.4s内通过的路程为4m,而位移为零 |
C.4s末物体离出发点最远 |
D.加速度大小不变,方向与初速度方向相同 |
B
试题分析:由图看出,质点的速度先为正后为负,说明质点先沿正方向运动,后沿负方向运动.故A错误.前2s内质点的位移为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001936130798.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001936146508.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001936162797.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001936240521.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001936255547.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001936271470.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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