Answer:
Let's define t = 0 as the moment when the ball hits the wall.
in this moment, we have a given acceleration, but if we only want to calculate the average acceleration, then let's consider the acceleration constant.
a(t) = A.
To find the velocity equation we should integrate, and the constant of integration will be the initial velocity, in this case, is 14.3m/s.
v(t) = A*t + 14.3m/s
Now we know that at t = 0.011s, the velocity is -13.5m/s (the sign is negative because the ball is moving in the opposite direction as before).
Then we can solve the equation:
v(0.011s) = -13.5m/s = A*0.011s + 14.3m/s
Now we can solve it for A, the average acceleration:
-13.5m/s - 14.3m/s = A*0.011s
(-27.8m/s)/0.011s = A = -1313.5 m/s^2
