9 A solid wooden cylinder of radius r, height h, and specific gravity sw is placed in a container of tap water such that the axis of the cylinder is perpendicular to the surface of the water. Assume that the density of the water is . It is assumed the wooden cylinder stays upright under small oscillations. a) If the cylinder is displaced a small amount, then determine an expression for its natural frequency. b) If the tap water is replaced by salt water with specific gravity of 1.2, then determine whether the natural frequency of the wooden cylinder increases or decreases and by what percentage.