E² = p²c² + (mc²)²

1. Feb 19, 2005

quasar987

.....................................

Last edited: Feb 19, 2005
2. Feb 19, 2005

dextercioby

Who's ita_{0,x,y,z) ??

Daniel.

3. Feb 19, 2005

quasar987

As it often happens I found the answer to my question while typing it :tongue2:

$\eta$ was for the proper speed... i.e. $\eta_{0,x,y,z}$ are the components of the four-velocity. What symbol do you use?

4. Feb 19, 2005

dextercioby

Ita is for the metric...$u_{\mu}$ is the four-velocity...

Daniel.

5. Feb 19, 2005

quasar987

What's a 'metric' ?

6. Feb 19, 2005

dextercioby

A distance,in mathematics (a metric space is a topological space with a metric)...Here,in physics jargon,it stands for the metric tensor $g_{\mu\nu}$ for spacetime and for the flat Minkowski spactime $\eta_{\mu\nu}$

Daniel.

7. Feb 21, 2005

krab

quasar: $\eta$ is pronounced like something between etta and ayta; not eeta.

8. Feb 21, 2005

dextercioby

In Neogreek it is pronounced ITA (eeta,if u want to).True,in Anciant Greek it's ETA...

Daniel.