So I have this problem:(adsbygoogle = window.adsbygoogle || []).push({});

A massmtravels to the right at 4c/5, and another massmis at rest.

They ask fro the energy and momentum of each particle, so I have:

Energy of traveling: 5/3 mc^2

Energy of rest: mc^2

Momentum of traveling: 4mc/3

Momentum of rest: 0

Then they ask for the velocity of the CM of the system:

Which I have 2c/5, but then some people are telling me c/2.

But anyway, I have to solve for the velocities of the particles in the CM frame, so how I do go from there.

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# Energy, momentum and CM

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