Given data
The magnitude of the total force is F = 210 N
The mass of the rock is m = 0.23 kg
The length of the string is L = 0.35 m
The expression for the maximum angualr velocity is given as:

Substitute the value in the above equation.
![\begin{gathered} \omega=\sqrt[]{\frac{210\text{ N}}{0.23\text{ kg }*\text{0.35 m}}} \\ \omega=51.07\text{ rad/s} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/3f221xft3ruj12jkc3jfzjnm6iwgqdhr3t.png)
Thus, the maximum angular velocity of the rock is 51.07 rad/s.