Two particles are shown in the figure. At t=0, a constant force F=6 N starts acting on the 3 kg man.Find the velocity of the centre of mass of these particles at t=5 s

Method 1: Acceleration of 3 kg:  a2=63=2m/s2 Velocity of 3kg at t=5s:v2=u2+a2t=0+2×5=10m/svCM(t=5s)=2×0+3×102+3=6m/sMethod 2:aCM=Fm1+m2=62+3=1.2m/s2vCM=uCM+aCMt=0+1.2×5=6m/s