Longitudinal Wave
A wave in which medium particles oscillate parallel to the direction of wave energy propagation.
Governing formula
s(x,t) = s_max cos(k x - ω t)
SI unit
m
In depth
Longitudinal waves consist of alternating high-density compressions and low-density rarefactions. They can travel through solids, liquids, and gases.
Examples in the real world
Sound waves traveling through air, primary seismic P-waves, and compression waves along a slinky spring.