题目内容
质量为m的物体静止在光滑水平面上,从t = 0时刻开始受到水平拉力的作用力的大小F与时间t的关系如图所示,力的方向保持不变,则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241347050238155.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241347050238155.png)
A.t0时刻的瞬时速度为![]() |
B.在t = 0到t0这段时间内拉力做功为![]() |
C.![]() ![]() |
D.在t = 0到![]() ![]() |
D
由动量定理可知在0-t0时间内
,A错;t=t0时刻,根据动量定理可知此时速度为
,由动能定理拉力做功为
,B错;在
时刻根据动量定理求得瞬时速度
,瞬时功率P=
,C错;物体动能增量为
,即为拉力做的功,平均功率为![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134705694796.png)
,D对;
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241347053821014.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134705413584.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134705460907.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134705179400.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241347055541180.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134705601924.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241347056471016.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134705694796.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134705320768.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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