A ball weighing 100 g, flying at a speed of 20 m / s, hit a vertical plane and rebounded. Find the change in the ball

A ball weighing 100 g, flying at a speed of 20 m / s, hit a vertical plane and rebounded. Find the change in the ball if the impact is absolutely elastic. What is the elastic force generated by the impact if it lasted 0.1 s

Given:
m = 100 g;
V = 20 m / s;
T = 0.1 s.
Find the momentum p.
Decision:
1) We use the formula Δp = mv2 – (- mv1).
2) Substitute all known values
Δp = 0.1 * 20 + 0.1 * 20 = 4 kg * m / s FΔt = Δp
3) We use the formula F = Δp / Δt = 4 / 0.1 = 40 N
Answer: 40 N