(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Calculate the kinetic energy of an electron whose momentum is 2MeV/c.

2. Relevant equations

[tex]P=\gamma m_0 v =mv[/tex].

[tex]E_K=(m-m_0)c^2[/tex].

3. The attempt at a solution

I'm told that [tex]\gamma m_0 v=\frac{2MeV}{c}[/tex].

If only I had the mass at rest of the electron (it isn't given in the problem), I could calculate its velocity with the first formula I gave. Then I could calculate its mass (not its rest mass, its apparent mass or whatever it's called). And then I could apply the third formula and this would solve the problem. Am I right?

So, should I look for the electron's rest mass in some book? Is there a missing data, or can I solve the problem without this info?

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# Homework Help: Kinetic energy, special relativity

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