Can't forget about friction coefficient though...

Where would we be without friction? Somewhere incredibly fun, that's where.
( Incredibly Ordinary Dave needs your clothes, your boots and your motorcycle, Thu 20 Dec 2007, 0:03, archived)

and that old favourite
permeability
( my other username is a porsche , posting shit pictures so you don't have to, Thu 20 Dec 2007, 0:06, archived)