Block `B` of mass `2 kg` is placed on smooth horizontal plane. Block `A` to mass `1 kg` is placed on block `B`. The coefficient of friction between `A` and `B` is `0.40`. The block `A` is imparted a velocity `16 m//s` "at" `t=0`. Find the time at which momentum of the twoblocks are equal ( in seconds). `(g=10m//s^(2))`