Answer:
The average force exerted on the superball by the sidewalk is 0.00122 N.
Step-by-step explanation:
Given;
mass of the super ball, m = 50 g = 0.05 kg
initial velocity of the super bowl, u = -27 m/s (assuming downward motion to be negative)
final velocity of the super bowl, u = 17 m/s (assuming upward motion to be positive)
time of motion, t = 1800 s
The average force exerted on the superball by the sidewalk is given by;

Therefore, the average force exerted on the superball by the sidewalk is 0.00122 N.