Robin, Yes it is confusing. Also sometimes the phase velocity appears to be greater than c (anomalous media) or the group velocity is. In either case they defer to the one less than c. The Feynman articles give a proof relating Quantum Mechanics (expressions for E and p) to the relation in Special Relativity that seems to provide a proof that it is the group velocity that is relevant.
Remi. -----Original Message----- From: Robin van Spaandonk [mailto:[EMAIL PROTECTED] Sent: 26 September 2006 04:57 To: [email protected] Subject: Re: [Vo]: stationary emdrive- inertial anchor In reply to Remi Cornwall's message of Mon, 25 Sep 2006 20:21:56 +0100: Hi Remi, [snip] >Don, > >I had a few thoughts on the paper: >http://uk.geocities.com/remicornwall/ElectromagneticPropulsion.htm In http://uk.geocities.com/remicornwall/FeynmanIIpg24a7sections24a2to24a4.jpg it states very explicitly: "The group velocity of the waves is also the speed at which energy is transported along the guide". Which is what I always thought it was. However Andreas Rathke states in his paper "The Energy of a wave is transported at its phase velocity". (See page 1). One of them seems to be wrong. Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
