Waves and Sound

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Waves and Sound

• Honors Physics
• Chapter 14

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Definition of a wave

• A disturbance that propagates from 1 place to
  another.
• Characterized by a large transfer of energy
  without a large transfer of medium

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Types of waves

• Mechanical waves require a medium (air, water,
  ropes) to travel
• Electromagnetic waves do not require a medium to
  travel (light, radio)

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Mechanical Waves

• Transverse the displacement of the individual
  particles is perpendicular to the direction of
  propagation.

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Mechanical Waves

• Longitudinal The displacement of the individual
  particles is parallel to the direction of
  propagation.

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Waves in motion

• Longitudinal and Transverse Wave Motion

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Properties of waves

1. Amplitude (A) the maximum displacement from
   equilibrium position, measured in meters.
2. Wavelength ( ?) the distance between 2 particles
   that are in phase with each other, measured in
   meters.

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Wave diagram
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Properties of waves

• 3. Frequency (f) number of complete waves that
  pass a point in one second, measured in 1/seconds
  or Hertz (Hz)
• 4. Period (T) the time it takes for one complete
  wave to pass a given point, measured in seconds.

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Properties of waves

• Velocity of propagation (v) horizontal speed of
  a point on a wave as it propagates, measured in
  m/s.

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Relationships/equations

• T 1/ f
• or f 1/T
• v f ?

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Reflections

• Fixed End
• Explanation
• Animation
• Open End
• Explanation
• Animation
• Between different mediums scroll down (What do
  you notice about the phases? Transmitted?
  Reflected?)

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Principle of Superposition

• Occurs when two waves travel through the same
  medium at the same time.
• Each wave affects the medium independently.
• The displacement of the medium is the algebraic
  sum of the displacements.
• Animation (scroll down) new animation

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Interference

• Constructive occurs when wave displacements are
  in the same direction (in-phase) video
• Destructive occurs when wave displacement are in
  different directions (out-of-phase) video

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Frequency

• Light
• BACK

• Audible range 20-20,000 Hz (listen)