Human society itself is the expression of dynamic balance, including chaos, war and peaceful development. Physical dynamic balance, among the problems related to object balance, there are a lot of dynamic balance problems. The so-called dynamic balance problem is to make the state of an object change slowly by controlling a certain physical quantity. There are usually two methods to analyze dynamic equilibrium problems. 1. Analytical method: Analyze the stress of the research object in any state, establish an equilibrium equation, find out the general function expressions of strain parameters and independent variable parameters, and then determine the change of strain parameters according to the change of independent variable parameters. Graphic method: analyze the force of the research object, then draw the vector diagram of the force in different States according to the parallelogram rule or triangle rule (drawn in the same picture), and then judge the change of each force according to the length of the directed line segment (representative force).