题目内容
(10分)在粗糙水平面上有一质量为m=10kg的物体,物体与水平面的动摩擦因数为μ=0.2。现在对物体施加一个斜向下,与水平面成
=37°的推力F ,F=100N,物体由静止开始向右运动。作用5s后撤去外力F。g取10m/s2。(其中sin37°=0.6,,cos37°=0.8)求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250041288102391.png)
(1)力
作用下物体的加速度为多少?
(2)撤去外力F时物体的速度大小
(3)物体在水平面上发生的总位移
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004128779310.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250041288102391.png)
(1)力
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004128826302.png)
(2)撤去外力F时物体的速度大小
(3)物体在水平面上发生的总位移
(1)
(2)
(3)204m
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004128842570.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004128873558.png)
试题分析:(1)根据牛顿第二定律得,
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250041288883327.png)
(2)根据速度时间公式得,
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250041289041009.png)
(3)则匀加速直线运动的位移
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250041289351204.png)
撤去推力F后的加速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004128951800.png)
则匀减速直线运动的位移
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250041289661104.png)
所以
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004128998769.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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