题目内容
(9分)质量为m=2kg的物体原静止在粗糙水平面上, 现对该物体施加一与水平方向夹角θ=37º的斜向上拉力F=10N,如图所示,经t=10s后撤去力F,再经过一段时间,物体又静止,已知物体运动过程中的最大速度是5m/s。(sin37º=0.6)求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250007229141298.png)
(1)物体与水平面间的动摩擦系数μ是多少?
(2)物体运动的总位移是多少?(g取10m/s2。)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250007229141298.png)
(1)物体与水平面间的动摩擦系数μ是多少?
(2)物体运动的总位移是多少?(g取10m/s2。)
(1)μ="0.5" (2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000722929748.png)
试题分析:(1)前10s一直做匀加速运动,
则:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000722960813.png)
物体的加速度为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000722976694.png)
由:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250007229921086.png)
它们之间的动摩擦系数μ=0.5 (1分)
(2)前10s的位移:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000723007851.png)
接下来物体做匀减速度运动
加速度:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000723023805.png)
位移:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000723023895.png)
则总位移
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000722929748.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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