作图给出杠杆上的“最小力”是对杠杆平衡条件的应用,是考察学生思维能力的好题.近几年中考中这样的题目频频出现,通过自己的教学实践,对解决这类问题的方法进行分析归纳,以供参考.一、动力作用点固定时的最小力例1如图1所示.在A点作出使杠杆平衡的最小力的示意图.例2如图2所示.在弯曲杠杆A端吊一重物G,要想在B端加一最小的力F,使 Drawing gives the lever on the “minimum force” is the application of the lever balance conditions, is to examine the thinking ability of students a good topic in recent years in the test in the frequent occurrence of such problems, through their own teaching practice, to solve this Class problems of the method for analysis and induction for reference.First, the dynamic force point fixed when the minimum force 1 shown in Figure 1. Make a lever at Leverage the minimum force diagram.Example 2 shown in Figure 2 Lifting a heavy object in the bending lever A G, in order to add a minimum force B at the end, so