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SHM, WAVE MOTION & SOUND - Coggle Diagram

- - - - Measured in Hertz( Hz)
        
        50 Hz = 50 vibrations in one second
  - - - distance/time
    - - period=time
      - wavelength=distance
    - - V
        
        Frequency x λ
        
        λ / period
  - - - When a wave strikes an interface in case of open boundary it will get reflected as well as refracted.
    - - When a wave is incident on an interface it will completely get reflected
- - - - the speed depends on the fluid's compressibility and inertia
    - - sound travels faster in solids than in fluids and gases
    - - sound travels slowest through gases
  - - - wavelength is distance between each successive region of high or low pressure
      - sound is simply any longitudinal wave in a medium
      - frequency is number of oscillations in pressure per second
    - - the harmonic content greatly affects our perception of sound
  - - - the greater the amplitude of the fluctuations in the pressure, the louder the sound appears.
    - - the intensity of a sinusoidal sound wave is proportional to the square of the amplitude, the square of the frequency, and the square of the pressure amplitude.
    - - but intensity DECREASES with distance more slowly than 1/r^2 when the sound goes predominantly in one direction.
    - - units of sound level intensity: decibels (dB), a logarithmic scale.
  - - - different sizes produce tones with different frequencies
      - harmonics in an open pipe
        
        an open pipe is open at both ends
        
        harmonics in a closed pipe
        
        a closed pipe is open at one end and closed at other end
  - - - a dramatic INCREASE in amplitude occurs
  - - - constructive interference results in antinodes and occurs whenever a thick line meets a thick line.
        
        thus listeners at the antinodes hear the sound from the sources better than listeners at the
        nodes.
    - - $diffraction1$
  - - - example: a passing car
    - - it is called doppler effect.
    - - giving a higher pitch since the velocity of the wave is UNCHANGED. Similarly the pitch of a receding sound source will be lowered.
  - - - an aircraft travelling through the atmosphere continously produces air-pressure waves similar to the water waves caused by a ship's bow
      - when the aircraft exceeds the speed of sound, these pressure waves combine and form visible shock waves
      - supersonic is faster than the speed of sound
      - sonic boom is sharp crack heard when conical shell of compressed air that sweeps behind a supersonic aircraft reaches listeners on the ground
    - - Mach number is speed of object over speed of sound
  - - - fundamental and harmanics dissonance and consonance
    - - most pieces of music set up a limited amount of dissonance on purpose and then resolve it to a consonant conclusion.
      - noise contains a great deal of dissonance and provides no relief.
    - - intensity is interpreted by the human brain as loudness
      - frequency is interpreted by the human brain as pitch
      - harmonic content is interpreted by the human brain as a component of the timbre
  - - - attack and decay
        
        describes how quickly the amplitude of the sound reaches a maximum and how quickly it dies out
      - vibrato/tremolo
        
        vibrato is periodic changes in the pitch of the tone. It is called frequency modulation of tone
        
        tremolo is used to indicate periodic changes in the amplitude or loudness of the tone. It is called amplitude modulation of tone
      - harmonic content (the most IMPORTANT contributor)
- - - - Energy variation with displacement,
      - Energy variation with time,