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ok idk if im right and the book is wrong but help me out the question is...

An electron moving at a speed 0.60c collides head on witha positron also moving at 0.60c. Determine the energy and momentum of each photon produced in the process.

well this is what I did..

[tex] E = 2\frac{m_ec^2}{ \sqrt{1-\frac{(0.6c)^2}{c^2}}}[/tex]

[tex] E = 255864.36 \ eV = 0.256 \ MeV [/tex]

the book says the energy is E = 0.64 MeV why?

i figured E = m_e c^2 + KE but it my calcs must be off or something i don't understand

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# Homework Help: What the ?

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