# Homework Help: Difference between speed and celerity?

1. Sep 8, 2006

### mohlam12

okay, just a simple question...
what is the difference between speed and celerity?
thanks :)

2. Sep 8, 2006

### Integral

Staff Emeritus
To the best of my knowledge "celerity" has no meaning in physics.

3. Sep 8, 2006

### robphy

In relativity, celerity has been used to describe the quantity $$\frac{1}{\sqrt{1-v^2/c^2}}v$$, where $$v$$ is the velocity (whose magnitude is the speed).