通过对人教版八年级物理《杠杆》中的图例的分析,结合自己教学实践活动中,对见到的有关杠杆的一类问题作了阐释,同时对教材中所做出的撬棒在撬动石头的阻力作用进行了受力分析和说明,认为教材中在处理此时撬棒受到的石头的阻力方向存在问题。 Through the analysis of the illustrations in the “Leverage” of PEP in the eighth grade of PEP, combined with one's own teaching practice activities, I explain the one kind of problems about the levers I saw, at the same time I pry the crowbar The resistance of moving stones was analyzed and explained by force, which indicates that there is a problem in the teaching materials in handling the direction of the resistance of the stone received by the pry bar.