Darren New wrote:
> Mueen Nawaz wrote:
>> Darren New wrote:
>>> Nope. Electric charge, yes, but not mass. Photons will have mass 
>>> proportional to their frequency, and frequency isn't apparently 
>>> quantified.
>>
>>     Define mass.
> 
> E=mc^2?  Isn't mass measured in electron-volts?
> 
> Why? What's your point?  (This isn't sarcastic. I don't know enough to 
> know why someone who knows more would point out that I didn't define 
> mass, or that my naive understanding of it isn't correct.)

	The usual convention I've seen is to state that photons have momentum, 
not mass. A lot of physics textbooks (these days) don't talk about 
relativistic mass or mass changing when one speeds up.

	The original formalism by Einstein did have the mass changing.

	I'm not saying your definition is inconsistent, but I think physicists 
did not like the suggestion that a body gains more mass just by going 
faster.

You can see a bit of it here:

http://en.wikipedia.org/wiki/Mass_in_special_relativity#Controversy

	I'm used to people meaning "rest mass" when they just say mass. And a 
photon has 0 rest mass.

	Doing a Google search, it seems people are divided as to what they call 
"mass". For example, the American Institute of Physics page here 
casually refers to the rest mass as simply mass:

http://www.aip.org/pnu/2003/split/625-2.html

	Nothing deep - just wanted to make sure we were talking about the same 
thing.

-- 
A closed mouth gathers no feet...


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