Answer:
Step-by-step explanation:
Comment
It's actually a deceleration. You should get a negative answer because the ball is slowing down.
Givens
vi = 8.09 m/s
vf = 5.87 m/s
t = 9.17
Formula
a = (vf - vi) /t Substitute the givens into the formula
Solution
a = (5.87 - 8.09)/9.17
Answer
a = - 2.22 m/s^2