Sound

1
Sound

• Introduction
• Longitudinal waves with regions of high and low
  pressure that travel through a medium
• Audible, Infrasonic, Ultrasonic
• Speed of sound varies with temperature and
  density of the medium
• 343 m/s at 23C in air

2
Sound

• Sound Waves
• Regions of condensation and rarefaction
• Example
• The particles experience simple harmonic motion
  as the wave passes them
• Remember that the particles are already moving
  when the wave reaches them.

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Sound

• Doppler Effect
• Apparent change in the frequency of the wave due
  to motion of the source or observer
• Sound (trains, sirens) and light

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Sound

• Supersonic Speed and Shock Waves
• Shockwave and Mach cone

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APHY101
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Wave Superposition and Interference

• Superposition
• Adding the displacements of two or more waves
  that are interacting.
• Constructive and destructive

6
Wave Superposition and Interference

• Standing Waves
• Adding of two identical waves moving in opposite
  directions
• Simulation
• Nodes and Antinodes
• String and wind instruments

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Wave Superposition and Interference

• Harmonics

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Wave Superposition and Interference

• Harmonics

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Wave Superposition and Interference

• Beats
• Interference of two sounds with different
  frequencies
• Tuning instruments in an orchestra

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