To solve this problem, we should remember that the formula for angular acceleration is:
α = Δω / Δt
Where,
α = angular acceleration
ω = angular velocity
t = time
Substituting the known given values:
α = (30 rev / min – 50 rev / min) * (1 min / 60 s) / 5 s
α = - 0.067 rev / s^2
We can see that the values is negative since the potter’s wheel is decelerating.