Question

A wheel with rotational inertia I is mounted on a fixed, frictionless axle. The angular speed ω of the wheel is increased from zero to ωf in a time interval T.
What is the average power input to the wheel during this time interval (hint: power = work / time)?

A:$\frac{I^{2}\omega_{f} }{2T^{2} }$
B: $\frac{I\omega^{2}_{f} }{2T^{2} }$
C: $\frac{I\omega_{f}} {2T}$
D: $\frac{I\omega^{2}_{f} }{2T}$