Student Friendly Introduction to QFT · Problem 12.1

Renormalization: Putting It All Together

Physics — QFT · center-of-mass-momentum

Problem

In case your freshman physics is a little hazy, find the center of mass

x_m

of two masses

m_1

and

m_2

, located respectively at

x_1

and

x_2

. Then take the time derivative of

(m_1 + m_2)x_m

to get the total 3-momentum of the system. If we are in another, primed, coordinate frame that is fixed to the COM of the system of particles, what is the velocity of the COM of the system in that primed coordinate frame? What is the total system 3-momentum as measured in the primed coordinate frame, i.e., in the COM frame?

Related theory

Center Of Mass

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