Chapter 12 Oscillations §12-2 Simple Harmonic Motion(SHM(简谐振动)P29304 物体运动时,如果离开平衡位置的位移(或角位 移)按余弦函数(或正弦函数)的规律随时间变化, 这种运动叫简谐运动 x=4co(+() x是描述位置的物理量,如y,z或θ等 Any vibrating System for which the net restoring force(A a f )is directly proportional to the negative of the displacement is said to exhibit simple harmonic motion. The displacement varies sinusoidally with time. This type of motion is referred to as Simple Harmonic Motion (SHM). P299
Chapter 12 Oscillations Any Vibrating System for which the net restoring force ( 回 复 力 )is directly proportional to the negative of the displacement is said to exhibit simple harmonic motion. The displacement varies sinusoidally with time. This type of motion is referred to as Simple Harmonic Motion (SHM) .p299 §12-2 Simple Harmonic Motion (SHM) (简谐振动） P299-304 物体运动时，如果离开平衡位置的位移（或角位 移）按余弦函数（或正弦函数）的规律随时间变化， 这种运动叫简谐运动。 x = Acos(t +) x是描述位置的物理量,如 y , z 或 等
Chapter 12 Oscillations The simple harmonic,合振动 motion is the most simple X 分振动1 and basic vibration. Every 分振动2 complicated vibration can F be considered as composing of several shm 物理上:简谐运动是最简单、最基本的振动。一般 运动是多个简谐运动的合成。 合成 简谐运动 分解复杂振动
Chapter 12 Oscillations x t o 2 T T 2 3T 2T 合振动 分振动1 分振动2 The simple harmonic motion is the most simple and basic vibration. Every complicated vibration can be considered as composing of several SHM. 简谐运动 复杂振动 合成 分解 物理上：简谐运动是最简单、最基本的振动。一般 运动是多个简谐运动的合成
Chapter 12 Oscillations 简谐运动可以用一个弹簧振子( spring 弹簧振子:一个轻质弹簧的一端固定,另一端固结 个可以自由运动的物体,就构成一个弹簧振子。 k x=01F=0 O am OX
Chapter 12 Oscillations l k 0 x m − A o A x = 0 F = 0 x x F m o 简谐运动可以用一个弹簧振子(spring) 弹簧振子：一个轻质弹簧的一端固定，另一端固结一 个可以自由运动的物体，就构成一个弹簧振子
Chapter 12 Oscillations I Motion Function of SHM (P299-300) F ^2=0 Object: block-spring system; x=0 x=A (b) Origin: equilibrium position max 0 Restoring force: F (c) F U=0 A=-A A=o 个作简谐运动的质点所受的 F=0 沿位移方向的合外力与它对于 x=0 平衡位置的位移成正比而反向, A这样的力称为回复力。 r=o r=A
Chapter 12 Oscillations Object: block-spring system; Origin: equilibrium position Restoring force: F 1 Motion Function of SHM (P299-300): 一个作简谐运动的质点所受的 沿位移方向的合外力与它对于 平衡位置的位移成正比而反向， 这样的力称为回复力
Chapter 12 Oscillations X From hooke's law and n-ii law F=-h=ma let ok C=-0x Equation of motion for the d-x d,2 +ar=0 Simple harmonic oscillator. 简谐运动的动力学方程 Mathematically it is called a differential equation
Chapter 12 Oscillations F = −kx = ma m k = 2 let a x 2 = − x x F m o From Hooke’s Law and N-II law : 0 d d 2 2 2 + x = t x Equation of motion for the simple harmonic oscillator. 简谐运动的动力学方程 Mathematically it is called a differential equation