Answer
The frequency of oscillation is $0.63~Hz$
Work Step by Step
We can find the period of a physical pendulum:
$T = 2\pi~\sqrt{\frac{I_{support}}{mgL_{cm}}}$
$T = 2\pi~\sqrt{\frac{0.25~m^2}{(9.80~m/s^2)(0.40~m)}}$
$T = 1.587~s$
We can find the frequency:
$f = \frac{1}{T}$
$f = \frac{1}{1.587~s}$
$f = 0.63~Hz$
The frequency of oscillation is $0.63~Hz$.
