A steel shaft has torsional stiffness $k_t = \\frac{G J}{L}$, where $G = 10$ GPa, $J = 2 \\times 10^{-5}$ m$^4$ (polar moment of inertia), and $L = 2$ m. A flywheel with rotational inertia $I = 10$ kg\cdot m$^2$ is attached at the free end. What is the natural frequency of torsional vibration $\\omega_n = \\sqrt{\\frac{k_t}{I}}$?