Why was the derivation reverted? The page in its current form is useful to no one. The page with the derivation was at least useful and interesting to people with a basic background in physics.
I'm all for a revision to make this page more accessible to people who don't know physics. But until that happens, I think that contribution was certainly an improvement to what's here. I'd work on a new page myself, but I don't have the physics background to do a good job of it. --MarkGall 19:40, 29 September 2009 (EDT)