In this chapter, we will study the most important periodic motion- Simple harmonic motion(简谐 振动), which is base to investigate(研究)the complex periodic motion. 复杂运动 平衡位置 周期运动 简谐振动——波动、电磁波、电压电流等In this chapter, we will study the most important periodic motion-------Simple Harmonic Motion(简谐 振 动 ), which is base to investigate( 研 究 ） the complex periodic motion. 简谐振动 周期运动 复杂运动 波动、电磁波、电压电流等等