Answer:
The momentum of the two balls if they stick together after the collision is 0.6 kgm/s.
Step-by-step explanation:
Apply the principle of conservation of linear momentum, the total momentum before collision is equal to the total momentum after collision.
Given;
initial momentum of the cue ball = 0.5 kgm/s
initial momentum of the 8 ball = 0.1 kgm/s

Therefore, the momentum of the two balls if they stick together after the collision is 0.6 kgm/s.