17.2 Properties of Mechanical Waves Notes


Amplitude- Maximum displacement of the medium from its rest position
  • The more energy the wave has the more medium will be compressed or will be displaced
  • More energy the wave has the greater is its amplitude
  • Crest- higher part of wave
  • Trough- lower part of wave

Frequency- The number of complete cycles per unit time for a periodic motion

  • The number of complete cycles in a given time
  • waves frequency equals the frequency of the vibrating source producing the wave
  • measured in: Hertz (Hz)noise-canceling-headphone-8.jpgfrequency.jpg

Wavelength- Distance between a point on one wave and the same point on the next cycle of wave
  • Increasing the frequency of a wave decreases its wavelength


Speed- Ratio of the distance an object moves to the amount of time an object moves

  • If you assume that waves are traveling at a constant spped, then wavelength is inveresely proportional to frequency
  • Speed can change if it enters a medium or if pressure and/or temperature changes
  • Unit for speed: meters/second
  • 1Hz = 1/s
Formula to find speed: speed = wavelength x frequency
ex) One end of a rope is vibrated to produce a wave with a wavelength of 0.25 meters and the frequency is 3.0 Hz.
speed = 0.25m x 3.0 Hz
0.25m x 3.0 1/s
speed = 0.75 m/s