Step-by-step explanation:
It is given that,
Mass of both green and red ball, m₁ = m₂ = 0.5 kg
Initial speed of green ball, u₁ = 10.5 m/s
Initial speed of red ball, u₂ = 0 ( rest )
Final speed of green ball, v₁ = 0 (it stops)
We need to find the final speed of the red ball after the collision. Lt it is equal to v₂. Using the conservation of momentum as :



Since, m₁ = m₂

So, the final speed of red ball after the collision is 10.5 m/s. Hence, this is the required solution.