Hi all, apologies for cross posting, but I really need some sanity checking done on these equations, especially in my proving [math]E=mc^2[/math] from the Planck constant.

 

http://www.scienceforums.net/forum/showthread.php?p=414167

 

I think the SFN Mods would probably prefer comments in the originating thread.

 

Cheers.

Edited June 14, 200817 yr by nstansbury

E²=(mc²)²+(pc)²

Yep that's what I have too - I don't follow?

For stationary objects the pc term is 0.

For stationary objects the pc term is 0

 

Electromagnetic waves aren't stationary - they have momentum themselves.

Electromagnetic waves aren't stationary - they have momentum themselves.

 

Yep and for EM waves the mc² part is 0.

 

For a moving massive object neither term are 0.

Yep and for EM waves the mc² part is 0.

 

For a moving massive object neither term are 0.

 

I beg to differ:

 

[math]p=\frac{h}{\lambda}=\frac{E}{c}[/math]

 

http://en.wikipedia.org/wiki/Momentum#Momentum_in_relativistic_mechanics

I beg to differ:

 

[math]p=\frac{h}{\lambda}=\frac{E}{c}[/math]

 

http://en.wikipedia.org/wiki/Momentum#Momentum_in_relativistic_mechanics

 

E²=(mc²)²+(pc)²

 

m=0

 

E²=0+(pc)²

 

=>E=pc

 

Which is the same as you said. So we do infact agree...

Yep and for EM waves the mc2 part is 0.

 

Apologies, I miss read - thought you were suggesting the pc value was 0.

do bear in mind that being a relativistic equation you should be careful about what you mean by moving and stationary.