The average angular acceleration is defined as which expression?

• A. alpha = delta omega / delta t
• B. alpha = delta v / delta t
• C. alpha = omega / t
• D. alpha = delta theta / delta t

Answer: (A)

Average angular acceleration is the rate at which angular velocity changes with time. It is defined as α_avg = Δω / Δt, where Δω is the change in angular velocity and Δt is the time interval. This gives units of rad/s^2, matching the idea of a rate of change of velocity in rotational motion. The other expressions describe different quantities: Δv/Δt is linear acceleration, Δθ/Δt is average angular velocity, and ω/Δt does not generally represent a meaningful quantity for angular acceleration since it omits the required change in ω over the interval.