题目内容
如图所示,一块橡皮用细线悬挂于O点,现用支铅笔贴着细线的左侧水平向右以速度v匀速移动,运动过程中保持铅笔的高度不变,悬挂橡皮的那段细线保持竖直,则在铅笔未碰到橡皮前,橡皮的运动情况是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250026076763632.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250026076763632.png)
A.橡皮的运动轨迹是一条直线 |
B.橡皮在水平方向上作匀速运动 |
C.橡皮在竖直方向上作匀速运动 |
D.橡皮在图示位置时的速度大小为![]() |
B
试题分析:由于细线不可伸长,因此在t时间内,橡皮在竖直方向上的位移即为铅笔上方细线长度的变化,有:y=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002607707555.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002607722567.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002607738468.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002607754476.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002607769556.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002607785640.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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