A \(400 \mathrm{~kg}\) machine is placed at the midspan of a \(3.2-\mathrm{m}\) simply supported steel \(\left(E=200 \times 10^{9} \mathrm{~N} / \mathrm{m}^{2}\right)\) beam. The machine is observed to vibrate with a natural frequency of \(9.3 \mathrm{~Hz}\). What is the moment of inertia of the beam's cross section about its neutral axis?