使用单个动滑轮省一半力的条件

The Condition for Saving Half the Force Using a Single Movable Pulley

动滑轮是初中物理中一种比较重要的简单机械.部分学生对其工作时省力情况的认知较为模糊,不清楚省一半力的条件究竟有哪些.通过对动滑轮工作时的受力情况分析,厘清使用单个动滑轮省一半力的条件,对于学生更全面地认识动滑轮、滑轮组具有积极意义.

Pulley is the one of the more important the junior middle school physics simple machines.Part of the students’ awareness of the energy situation at work is relatively fuzzy,not clear exactly what save half force conditions.Through analyzing the force of the movable pulley to work, to clarify the use of a single movable pulley save half force conditions,for students to more fully understanding pulley,the pulley block has positive significance.