A cylindrical block of wood (density =650 kg m^-3 ), of base area 30 cm^2 and height 54 cm, floats in a liquid of density 900 kg m^-3. The block is…

A cylindrical block of wood (density $\displaystyle =650 \mathrm{~kg} \mathrm{~m}^{-3}$ ), of base area $\displaystyle 30 \mathrm{~cm}^2$ and height $\displaystyle 54$ cm, floats in a liquid of density $\displaystyle 900 \mathrm{~kg} \mathrm{~m}^{-3}$. The block is depressed slightly and then released. The time period of the resulting oscillations of the block would be equal to that of a simple pendulum of length (nearly) :