题目内容
(14分)如图所示,一光滑斜面固定在水平地面上,质量m=1kg的物体在平行于斜面向上的恒力F作用下,从A点由静止开始运动,到达B点时立即撤去拉力F.此后,物体到达C点时速度为零。每隔0.2s通过传感器测得物体的瞬时速度,下表给出了部分测量数据。求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250027576564034.png)
(1)恒力F的大小。(2)撤去外力F的时刻。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250027576564034.png)
(1)恒力F的大小。(2)撤去外力F的时刻。
(1)
(7分)(2)
(7分)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002757671517.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002757687452.png)
试题分析:(1)加速阶段加速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002757703971.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250027577341006.png)
加速阶段中:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002757749804.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002757765741.png)
由上两式得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002757781890.png)
(2)撤力瞬间物体的速度最大:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002757796747.png)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002757687452.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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