That is, power× power arm = resistance× resistance arm, which is expressed by algebraic expression as F 1 L 1 = F2 L2. Where F 1 stands for power, L 1 stands for power arm, F2 stands for resistance, and L2 stands for resistance arm. So to balance the lever, the power arm is several times that of the resistance arm, and the resistance is several times that of the power.
When using a lever, in order to save labor, a lever with a power arm longer than a resistance arm should be used; If you want to save distance, you should use a lever with a force arm shorter than a resistance arm. Therefore, the use of levers can save manpower and distance. However, if you want to save energy, you must move more distance; If you want to move less and invade each other's distance, you must work harder.