Yahoo Answers: Answers and Comments for What does it mean? [Physics]
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From mark
enGB
Fri, 18 Nov 2016 05:17:05 +0000
3
Yahoo Answers: Answers and Comments for What does it mean? [Physics]
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From D g: Photons have 0 rest mass
Rest mass is mass of...
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https://uk.answers.yahoo.com/question/index?qid=20161118051705AAi8f3Z
Fri, 18 Nov 2016 05:29:32 +0000
Photons have 0 rest mass
Rest mass is mass of object when at rest
Since photons always move at light speed they cannot exist at 0 m per second
If you look at relativity equations for mass the photon moving at c can have mass

From dawgdays: No, photons do not have mass.
The equation E ...
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Fri, 18 Nov 2016 08:55:38 +0000
No, photons do not have mass.
The equation E = mc^2 relates energy and mass, in that energy and mass can be converted, one to the other. What it does NOT say is that a photon (which is energy) also has mass.
But that equation is actually a short form. The full equation is
E^2 = m^2*c^4 + p^2*c^2
Where p is momentum. So while a photon has zero mass, it's energy has a momentum equivalent.