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I don't get something
Let's say a photon is moving in a vacuum. Everyone agrees that it's supposedly massless. But doesn't it have kinetic energy which is according to Einstein also mass? Also I know there is Plank equation on how to calculate energy of a photon, but
E = mc^2
E(k) = 1/2mv^2
mc^2 = 1/2mv^2, since it's moving at speed of light =>
mc^2 = 1/2mc^2
mc^2 = 0, since c is constant =>
m = 0
E = 0
both mass and Energy are equal to 0.
What's happening here?
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>>8758044
You got memed son
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>>8758044
E = mc^2 does only hold for non-moving objects, the photon has energy through its momentum
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>>8758044
Physicists realized that too, so they invented the concept of "rest mass." A photon doesn't have rest mass.
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>>8758044
What you have is only valid for a stationary particle, a photon can't be stationary so youv have to use thec more general version[math] E^2 = m^2 c^4 + p^2 c^2 [/math]when m=0 it'll still have momentum.
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>>8758044
E=mc^2 is not the actual equation, it's E^2=m^2c^4+p^2*c^2. The photon's rest mass is 0, so we en up with E=pc.
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>>8758049
Wrong. There is no rest mass, only invarient mass.
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>>8758055
Its the same thing
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>>8758056
Yes it is. My bad, I read rest as relativistic somehow.
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>>8758063
Only for nonrelativistic massive particles
Different types of particle can have different 'dispersions', or relations between mass and momentum (strictly, energy and momentum)
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