雀做杠杆类习题时,我们经常遇到“寻找最小力”类的题目,如何解答这类问题?一、正确画杠杆力臂的方法要正确画出杠杆上各力的力臂,首先要明确力臂的概念.力臂是从支点到力的作用线的垂直距离,而不是支点到力的作用点的距离.力臂的画法一般分如下几步:(1)根据题意确定支点O.(2)画好动力作用线和阻力作用线,必要时要用虚线将力的作用线延长.(3)从支点O向力的作用线作垂线,则从支 How to solve such problems? First, the correct way to draw the lever arm To draw the lever on the force of each force arm, first of all To clarify the concept of force arm.Left arm is the vertical distance from the fulcrum to the line of force, rather than the distance between the fulcrum and the point of force.Level arm generally divided into the following steps: (1) According to the title to determine Fulcrum O. (2) draw a good line of action and resistance lines, if necessary, the line of force will be used to extend the line of force. (3) from the fulcrum O to the line of force for the vertical, then the branch