题目内容
如图所示,传送带足够长,与水平面间的夹角α=37°,并以v=10 m/s的速度逆时针匀速转动着,在传送带的A端轻轻地放一个质量为m=1kg的小物体,若已知物体与传送带之间的动摩擦因数μ=0.5,(g=10 m/s2,sin37°=0.6,cos37°=0.8)则下列有关说法正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250039183324787.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250039183324787.png)
A.小物体运动1s后,受到的摩擦力大小不适用公式F=μFN |
B.小物体运动1s后加速度大小为2 m/s2 |
C.在放上小物体的第1s内,系统产生50J的热量 |
D.在放上小物体的第1s内,至少给系统提供能量70J才能维持传送带匀速转动 |
B
试题分析:由题意知,释放后A受向下摩擦力,根据牛顿第二定律
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003918347982.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003918363981.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003918379759.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003918394668.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003918410701.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250039184251058.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003918441927.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250039184571003.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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