- #1

davidge

- 554

- 21

$$ \bigg(\frac{1}{c^2} \frac{\partial^2}{\partial t^2} - \vec{\nabla^2} \bigg)u \big(\vec{x},t \big) = 0$$ ##c## is the speed of light. It corresponds to different quantities depending on what the system under consideretion is. For instance, for a simple vibrating string, ##c = \sqrt{T / \rho}## where ##T## is the tension and ##\rho## is the mass density per unit length.

My question is, What is the meaning of the ratio ## T / \rho = c^2##? Maybe, tension propagates at the speed of light throughout the string?