在各种物理模型、物理现象、物理规律中 ,普遍存在着和谐而优美的对称 .巧妙运用对称性 ,常能使一些复杂的问题变得简单 .一、利用对称思想分析1.平衡位置对称对有关平衡位置对称问题 ,应注意相关物理量在对称位置的大小关系 ,并在解题过程中加以利用。例 1　如图 1所示 ,小球 In a variety of physical models, physical phenomena, and physical laws, there is universal harmony and graceful symmetry. Ingenious use of symmetry can often make some complex problems simple. First, the use of symmetry analysis 1. Balanced position symmetry Regarding the symmetry of the equilibrium position, attention should be paid to the relationship between the size of the relevant physical quantity in the symmetrical position and be used in the process of solving the problem. Example 1 As shown in Figure 1, the ball