# Longitudinal Wave Equation meaning and derivation

by Enterprise D
Tags: longitudinal wave, transversal wave, waves
 P: 8 Hi, I have recently been studying waves, and I understand the transversal wave formula y=Asin(w(t-x/v)) which gives the y coordinate of a point at x along the x-axis in the instant t. However, Wikipedia (http://en.wikipedia.org/wiki/Longitudinal_wave) gives this as the equation for longitudinal waves too. If this is true, what does y represent? The displacement of a point relative to what? Also, does anyone know how to derive this formula specifically for longitudinal waves? Thanks very much!
 P: 2 For something such as a sound wave, Y represents the pressure at point x, at time t. It's a bit more challenging to visualize, but the formula is applied the same way.
 P: 861 For a longitudinal wave, y can also represent the displacement of particles in the medium. The displacement is to and fro parallel to the direction of propagation of the waves, whereas for a transverse wave the displacement is at right angles to the direction of propagation. The equation you quote can be used to represent either sort of wave.
P: 8