Physics - Transverse vs Longitudinal Waves

Intro to Waves

  • a wave is defined as - the transfer of energy without the transfer of matter, also known as wave motion
  • there are 2 types of waves that can transfer energy:

  
  1. transverse - particle vibrate at right angles to the direction of the wave, for example ocean waves
  2. longitudinal - particles vibrate in the same direction as the wave motion, but backwards and forwards, for example sound waves

 longitudinal vs transverse waves

  • the number of waves produced a second is called the frequency
  • there is no net change in transverse waves, and the wave travels away from its source
  • period - time for one wave to pass through a fixed point
  • wavelength - how long a wave is, measure peak to peak or trough to trough
  • amplitude - the heights of the wave, and the displacement from the rest position
  • frequency is measured in Hertz (Hz)
  • 1 wave passing a point = 1 Hz

The Seven Qualities of a Transverse Wave

  • wavelength (lambda)

  • frequency (Hz)

  • crest

  • trough - max downward value

  • amplitude - max upward value

  • period

  • wave speed

  • Everything is made up of atoms - even air has atoms

  • when one atoms bumps another, energy is transferred mechanically

  • mechanical energy transfer - one atom bumps another

  • vibration - a rapid continuous movement, creates sound waves

  • longitudinal waves are sometimes called pressure waves

  • longitudinal waves move to and fro in the direction of the energy flow

Calculating Wave Velocity

  • period - time needed to complete a wavelength
  • speed, frequency, and wavelength are linked by the wave equation
  • if frequency increases, wavelength decreases, and vice versa
  • wave equation - v = f λ
  • v = speed of wave (m/s)
  • f = frequency of wave (Hz)
  • λ = wavelength of wave (m)
  • to calculate frequency - f = v/λ
  • to calculate wavelength - λ = v/f