题目内容
质量为1kg的物体在光滑水平面内做曲线运动,已知该物体在互相垂直方向上的两个分运动的vx-t和vy-t图像分别如图所示.则下列说法正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241922009948144.png)
A.2s末质点的速度大小为7m/s B.质点所受的合外力大小为1.5N
C质点的初速度大小为5m/s D.2s内的位移大小为11m
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241922009948144.png)
A.2s末质点的速度大小为7m/s B.质点所受的合外力大小为1.5N
C质点的初速度大小为5m/s D.2s内的位移大小为11m
B
试题分析:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192201493364.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192202039785.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192202585621.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192203397823.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192204192894.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192204925910.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192205659454.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192206485889.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192207125479.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192207687784.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192208529759.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824192209356884.png)
故选B
点评:本题关键为根据图象得出x和y方向的分运动的运动规律,根据合运动与分运动的等效替代关系,得出合运动的速度与受力情况!
![](http://thumb2018.1010pic.com/images/loading.gif)
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