3.
(a)
xCoM = m 1x1 + m2x2
m1 + m2
vCom = Dxcom
dx
d(m1x1 +m2x2/m1=m2)
dt
m1dx1 + m2dx2
dt dt
(m1v1 + m2v2/m1 +m2)
(b)
Vcom = m1v1 + m2v2
m 1+ m2
Momentum of system along x axis = m1v1 + m2v2
Vcom = x