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

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• 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

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The Seven Qualities of a Transverse Wave

• wavelength (lambda)
• frequency (Hz)
• crest
• trough - max downward value
• amplitude - max upward value
• period
• wave speed

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• 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

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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

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