A proton of mass m undergoes a head-on elastic collision with a stationary carbon nucleus of mass 12×m. The initial velocity of the proton is 790 m/s in the positive x direction. Find the velocity of the center of mass of the system. I am really confused as to how to find the 'velocity of the center of mass'. I thought using the equation Mv = mv1 + mv2 would work but nope it surely didnt. I am not sure if I am missing an equation or what but I cant seem to figure it out. Thanks for your help and time!