Answer:
4 rad/s
Explanation:
The angular velocity is velocity over time:
[tex]\displaystyle{\omega = \dfrac{v}{r}}[/tex]
We know that the velocity is 20 m/s and the radius is half of diameter which is 10m/2 = 5 m. Hence, substitute in the formula:
[tex]\displaystyle{\omega = \dfrac{20 \: \text{m/s}}{5 \: \text{m}}}\\\\\displaystyle{\omega = 4 \: \text{rad/s}}[/tex]
Therefore, the angular velocity is 4 rad/s