Two point- like objects of masses 20g and 30g are fixed at two ends of rigid mass less rod of length 10cm. This system is suspended vertically from rigid ceiling using a thin wire attached to its centre of mass, as shown in the figure. The resulting torsional pendulum undergoes small oscillations the torsional constant of the wire is  $1.2\times {10}^{-8}Nmra{d}^{-1}$. The angular frequency of the oscillations is _____$rad/s$ .