The ball's acceleration while it is contact with the floor is 98.4m/s²
Explanation:
V1 = -√(2gh1) = -4.85 m/s
V2 = √(2gh2) = 4.1056 m/s
dV = V2 - V1 = +8.9556 m/s
a = dV/dt = 8.9556/0.091 = 98.4 m/s²
Therefore, the ball's acceleration while it is contact with the floor is 98.4m/s²