Mechanical Waves

• Particle's properties

  No size or dimension, does not super impose, Described by position
• Wave's properties

  Size depends on its amplitude, has pattern and spreads out, described by phase, frequency and wavelength
• Mechanical


  Requires source of disturbance, medium for its propagation, and physical mechanisms through which elements can influence each other.
• EM Waves


  Produced by accelerated charges
• Matter (probability waves)


  All microscopic particles, whether massless (i.e. photons) or having mass (i.e. electrons) have wave properties.
• Gravitational waves


  Result of vibration or movement in gravitational field
• Surface Waves


  have both transverse and longitudinal properties.
• Transverse Waves (e.g. wave in string


  The particle’s oscillation is perpendicular to the wave’s propagation.
• Longitudinal (Compressional) Waves (e.g. sound wave)


  The particle’s oscillation is parallel to the wave’s propagation.
• Wave pulse


  It is a single disturbance that moves through a medium from one point to another point
• Periodic wave


  Sinusoidal wave, standing wave, fourier wave
• Sinusoidal wave


  The disturbance oscillates periodically with a fixed frequency and wavelength
• Standing wave


  It is the superposition of two waves of the same frequency, wavelength, and amplitude travel in opposite directions'
• Fourier wave


  It is composed of superimposed sinusoidal waves
• compression


  a region with increased pressure and density
• rarefaction


  a region with deceased pressure and density
• Wavelength 


  Distance between two successive in-phase particles of the medium
• Distance of the crest (or trough) from equilibrium state of the wave.

  Amplitude
• Frequency


  The number of crest that pass a fixed point per second. (SI unit: hertz)
• Period


  The time (in second) it takes a wave to travel a wavelength.
• Angular frequency


  The rate of change of the phase of sinusoidal waveform
• Wave number


  The spatial frequency of a wave, either in cycles per unit distance or radians per unit distance.
• Epoch


  The initial phase or phase constant.
• Wave speed (Propagation or Phase speed


  The distance traveled by wave crest in one cycle divided by the period or the rate at which the phase of the wave propagates in space
• Group speed


  the rate at which the overall shape of the waves’ amplitude spreads through space
• Reflection


  It is the change in propagation direction at an interface between two different media
• Refraction


  It is the changing of wave propagation direction due to change in its transmission medium.
• Diffraction


  It is the bending of wave propagation when it encounters an obstacle or a slit.
• Interference


  It is the superposition of waves that encounter each other to create a new wave called an interference pattern.
• Intensity, I


  the time average rate at which energy is transported by the wave, per unit area, across a surface perpendicular to propagation’s direction
• Standing wave

  Node and antinode
• Node


  point in a standing wave that always undergoes complete destructive interference and therefore is stationary
• Antinode


  point in a standing wave, halfway between two nodes, at which the largest amplitude occurs
• Law of lengths


  for a vibrating string, its frequency is inversely proportional to its length.
• Law of diameters


  for a vibrating string, its frequency is inversely proportional to its diameter.
• Law of densities


  for a vibrating string, its frequency is inversely proportional to the square root of its linear density
• Law of tensions


  for a vibrating string, its frequency is directly proportional to the square root of the tension.
• Beats


  is the variation of loudness caused by amplitude variation
• String


  When the strings are disturbed by either plucking or strumming, they vibrate and produce sound. This sound is enhanced by the hollow body of the instrument.
• Winds


  One end of the instrument is blown, air inside it vibrates and produces sound.