Why and how in centre of mass chapter , we get m1r1 = m2r2 for two particles ?? Please derive it in a detailed manner . Share with your friends Share 1 Deepak Kumar answered this Dear student, x1=-r1x2=r2COM of system, x=m1x1+m2x2m1+m2⇒0=-m1r1+m2r2m1+m2⇒m1r1=m2r2 Regards 0 View Full Answer