题目内容
如图所示,人和物处于静止状态.当人拉着绳向右跨出一步后,人和物仍保持静止.不计绳与滑轮的摩擦,下列说法中正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250001518342103.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250001518342103.png)
A.绳的拉力大小不变 | B.人所受的合外力增大 |
C.地面对人的摩擦力增大 | D.人对地面的压力减小 |
AC
试题分析:由于绳的拉力大小总等于物体的重力,所以绳的拉力大小不变;由于人仍然静止,所以人所受的合外力等于零不变;人在水平方向满足
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000151834690.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000151850979.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目