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asdf1
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Why is the rest energy mc^2 of an electron or positron 0.51 MeV?
Because if it's not moving, why is there "c"?
Because if it's not moving, why is there "c"?
asdf1 said:isn't c= the speed of light =3.0*10^8?
asdf1 said:Why is the rest energy mc^2 of an electron or positron 0.51 MeV?
Because if it's not moving, why is there "c"?
It appears clear to me that you're asking why the rest energy is 0.51MeV. If so then I doubt anyone knows why. If there is then it lies outside of classical mechanics and dips into particle theory. As such I'd ask Reilly this question. He's the expert on that subject here.asdf1 said:Why is the rest energy mc^2 of an electron or positron 0.51 MeV?
Because if it's not moving, why is there "c"?
pmb_phy said:It appears clear to me that you're asking why the rest energy is 0.51MeV. If so then I doubt anyone knows why. If there is then it lies outside of classical mechanics and dips into particle theory. As such I'd ask Reilly this question. He's the expert on that subject here.
Pete
selfAdjoint said:No he's plainly asking why this rest energy is specified in tables as [tex]mc^2[/tex]. ....
Then I'd say follow the derivation and you'll see that the "c" has nothing to do with the velocity of the particle. This is not an expression likek kinetic energy where the velocity is that of the particle.asdf1 said:@@a
i was wondering why rest energy has "c" in it's formula~
because "c" is usually referred to as the speed of light, so i thought that it was weird to have something that is moving included in a "rest" energy formula~
asdf1 (lazy username, btw): one of Einstein's postulates providing the basis of special relativity states that the laws of nature must hold in any inertial frame of reference. Once he formulated SR, it became clear that many so-called laws did not fit the bill, so his next job was to rewrite these classical laws so that they did apply in all frames. You'll see 'c' popping up in all of these laws, since 'c' has a special significance in SR: it is required to translate co-ordinates and values from one frame to another, regardless of the velocity of these frames or the observables within. The reason why 'c' is so important is due to the other postulate of SR: that the speed of light in a vacuum is the same in all inertial frames. This speed limit is worked into relativistic mechanics by means of the Lorentz transformation, which gives us the rules of converting the co-ordinates of one frame to another.asdf1 said:@@a
i was wondering why rest energy has "c" in it's formula~
because "c" is usually referred to as the speed of light, so i thought that it was weird to have something that is moving included in a "rest" energy formula~