Introduction An infinite number of Varying force: F(tI ways in which a force may vary. particularly Periodic motion Vibration: a restoring force
Introduction Varying force: F(t) An infinite number of ways in which a force may vary. Periodic motion Vibration: a restoring force particularly
振动 仓 四季的变化 共振现象
四季的变化 共振现象 振动
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
8 14-1 Simple Harmonic Motion 简谐振动 1. The simple harmonic motion (abbreviate: SHM) The system( black- spring in Fig. 15-1 is h m: x called as a simple harmonic oscillator(谐 振子): 平衡位置 Spring:k不计质量。 Fig.15-1 body: m Equilibrium position: point o(和外力等于零); 物体:在平衡位置附近作周期性往复运动; 坐标原点:通常取为平衡位置o;
§14-1 Simple Harmonic Motion 简谐振动 1. The simple harmonic motion（abbreviate:SHM） The system ( blackspring) in Fig.15-1 is called as a simple harmonic oscillator( 谐 振子）： k m x Fig.15 −1 Spring: 不计质量。 body: k m Equilibrium position: point o(和外力等于零）; 物体：在平衡位置附近作周期性往复运动； 坐标原点：通常取为平衡位置o；
Spring: deformation x; km氵y氵 Body displacement x; 平衡位置 force: F=-kx(frictionless); Fig.15-1 acceleration F 2 =-=-0x→ =-0x =k dt 2 which solution is x=:A cos(at or: x =: Asin(at+ 9=9 2 This equation is called the harmonic equation
Spring: deformation x; Body: displacement x; force: (frictionless); acceleration: F = −kxx m F a = = − which solution is = + = + = + x Acos(t ) or x Asin(t ) This equation is called the harmonic equation. k m x Fig.15 −1 x dt d x a = = − m k =