Center Of Mass

A particle of mass '\(m\)' moving east ward with a speed '\(v\)' collides with another particle of same mass moving north-ward with same speed '\(v\)'. The two particles coalesce after collision. The new particle of mass '\(2 \mathrm{~m}\)' will move in north east direction with a speed (in \(\mathrm{m} / \mathrm{s}\) )