Answer:
1.75 m/s
Step-by-step explanation:
Momentum is conserved:
m₁ u₁ + m₂ u₂ = m₁ v₁ + m₂ v₂
(100 g) (2 m/s) + (200 g) (1 m/s) = (100 g) (0.5 m/s) + (200 g) v₂
2 m/s + (2) (1 m/s) = 0.5 m/s + 2 v₂
4 m/s = 0.5 m/s + 2 v₂
3.5 m/s = 2 v₂
v₂ = 1.75 m/s