Mass of a bomb m = 3 kg
Initial velocity of the bomb v = 0
Mass of the first part m1 = 2 kg
Velocity of the first part v1 = 3 m/s
Mass of the second part m2 = 1 kg
Let the velocity of the second part be v2 .
By the law of conservation of momentum
mv = m1v1 + m2v2
3 x 0 = 2 x 3 + 1 x v2
0 = 6 + v2
∴ v2 = -6 m/s
Velocity of the 1 kg mass = -6 m/s