Answer:
Approximately [tex]2.22\; {\rm rad\cdot s^{-1}}[/tex].
Explanation:
Each revolution increases the angular displacement of the propeller by [tex]2\,\pi[/tex] radians. Therefore, after [tex]10.6[/tex] revolutions, the angular displacement of the propeller will be [tex](10.6)\, (2\, \pi) = 21.2\,\pi[/tex] radians.
Divide angular displacement by the duration to find the angular velocity of this propeller:
[tex]\begin{aligned}\frac{21.2\, \pi\; {\rm rad}}{30\; {\rm s}} \approx 2.22\; {\rm rad\cdot s^{-1}} \end{aligned}[/tex].