Answer
$114.59 \dfrac{rev}{hour}$
Work Step by Step
The circumference is given by: $C=2 \pi r$
where $ r$ is the radius.
We know that the radius is half of the diameter (D).
Here $C=(2 ) (\pi)(\dfrac{1}{4})=\dfrac{\pi}{2}$
Thus, the angular speed $ \nu$ can be computed as:
$\dfrac{\nu}{C}=\dfrac {180 \ mph}{(\dfrac{\pi}{2}) \ \dfrac{miles}{rev}} \approx 114.59 \dfrac{rev}{hour}$
