If net force on a system of particles is zero. Then
`{:(,"Column I",,"Column II",),((A),"Acceleration of centre of mass",(p),"Constant",),((B),"Velocity of centre of mass",(q),"Zero",),((C ),"Momentum of centre of mass",(r ),"May br zero",),((D),"Velocity of an individual particle of the system",(s),"May be constant",):}`

Answer

(A) `rarr` q; (B) `rarr` p,r; (C ) `rarr` p,r; (D) `rarr` r,s