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Lecture 8Oscillations and Waves
http://web.njit.edu/~sirenko/http //web.njit.edu/ sirenko/
Physics 103 Spring 2012
2012 Andrei Sirenko, NJIT 1
Simple Harmonic Motion (SHM)11 A li d iA li d i1.1. Amplitude is Amplitude is
differentdifferent
22 Period (or frequency)Period (or frequency)2.2. Period (or frequency) Period (or frequency) is different.is different.
33 Phase is differentPhase is different3.3. Phase is different.Phase is different.
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Damping of harmonic oscillationsDamping of harmonic oscillations
Mechanical Energy Mechanical Energy 00
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WAVESWAVES11 M h i l WM h i l W1.1. Mechanical WavesMechanical Waves
2.2. Electromagnetic WavesElectromagnetic Waves
3.3. Material Waves (particles, like electrons, neutrons, Material Waves (particles, like electrons, neutrons, etcetc.).)
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Transverse Sinusoidal WavesTransverse Sinusoidal Waves
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The Speed of a Traveling WaveThe Speed of a Traveling Wave
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Wave Speed on a Stretched String Wave Speed on a Stretched String
TheThe speed of a wavespeed of a wave along a stretched ideal string dependsalong a stretched ideal string dependsThe The speed of a wavespeed of a wave along a stretched ideal string depends along a stretched ideal string depends only on the only on the tensiontension and and linear densitylinear density of the string and not on of the string and not on the frequency of the wave.the frequency of the wave.
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Energy and Power of a Traveling String WaveEnergy and Power of a Traveling String Wave
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∆E = Pavr × ∆ t
The Principle of Superposition for WavesThe Principle of Superposition for Waves
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The Principle of Superposition for WavesThe Principle of Superposition for Waves
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The Principle of Superposition for WavesThe Principle of Superposition for Waves
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Standing Waves Standing Waves
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Standing Waves / Fixed ends Standing Waves / Fixed ends
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Standing Waves / Fixed end / Resonance Standing Waves / Fixed end / Resonance
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SOUND WAVES:SOUND WAVES:
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TRAVELLING SOUND WAVES:TRAVELLING SOUND WAVES:
A A soundsound wave, traveling through a long airwave, traveling through a long air--filled tube with filled tube with speed speed vv, consists of a moving, periodic pattern of expansions , consists of a moving, periodic pattern of expansions
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pp g p p pg p p pand compressions of the air. and compressions of the air.
TRAVELLING SOUND WAVES:TRAVELLING SOUND WAVES:
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INTERFERENCE of the SOUND WAVES:INTERFERENCE of the SOUND WAVES:
N EN f h ND VEN EN f h ND VEINTENSITY of the SOUND WAVES:INTENSITY of the SOUND WAVES:
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The Decibel ScaleThe Decibel Scale::
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The Doppler EffectThe Doppler Effect For speeds For speeds vv less than less than
the the speed of soundspeed of soundthe the speed of soundspeed of sound
When the motion of detector or source is toward the When the motion of detector or source is toward the other the sign on its speed must give an upward shift in other the sign on its speed must give an upward shift in other, the sign on its speed must give an upward shift in other, the sign on its speed must give an upward shift in frequencyfrequency. When the motion of detector or source is away . When the motion of detector or source is away from the other, the sign on its speed must give a downward from the other, the sign on its speed must give a downward shift in frequencyshift in frequency
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q yq y
Supersonic Speeds; Shock Waves Supersonic Speeds; Shock Waves
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WAVES: QZ2WAVES: QZ2
The figure is a composite of three snapshots each of aThe figure is a composite of three snapshots each of aThe figure is a composite of three snapshots, each of a The figure is a composite of three snapshots, each of a wave traveling along a particular string. The phases wave traveling along a particular string. The phases for the waves are given by for the waves are given by
(a)(a) 22xx -- 44tt, ,
(b)(b) 44xx -- 88tt, and , and
(c)(c) 88xx -- 1616tt. .
Which phase corresponds to which wave in the figure?Which phase corresponds to which wave in the figure?Which phase corresponds to which wave in the figure?Which phase corresponds to which wave in the figure?
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SummarySummary
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Summary Summary
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