Re: What would the end velocity be if...?

finite guy wrote:

> Regarding rocket.html
> A photon is an 'object'.
> It's mass=0 but it has momentum...
> E=m*c^2 but a photon has energy...
> Is this not incongruent?

Well, photons can't undergo constant acceleration due to rocket thrust, 
so that's really relevant to the equations James was just talking about.

The answer to your question is that there is no problem with photons 
have no mass but having momentum and energy because the most general 
equation in special relativity relating energy, momentum, and mass is

	E^2 = m^2 c^4 + p^2 c^2.

For a particle at rest (p = 0), this decays to E = m c^2, the more 
familiar popularized Einstein equation.  For a massless particle like a 
photon (m = 0), this decays to E = p c, the equation relating a luxon's 
energy to its momentum.

-- 
Erik Max Francis && max@[EMAIL PROTECTED]
 && http://www.alcyone.com/max/
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