The red at the bottom is just the holder for the beaker. It’s not apart of the density.
Answer:
In a two particle system, the center of mass lies on the center of the line joining the two particles.
Impulse describes the change of momentum. Since we don't know the momentum of the soccer ball before the hit, this question is hard to answer. If you assume the momentum of the ball before the hit was p = 0, then the change in momentum is just Δp = Impulse = mv.
