Halliday, Resnick & Walker — Fluids: Problem 27

27 Figure 14-32 shows an iron ball suspended by thread of negligible mass from an upright cylinder that floats partially submerged in water. The cylinder has a height of 6.00 cm, a face area of 12.0 cm2 on the top and bottom, and a density of 0.25 g/cm3, and 1.00 cm of its height is above the water surface. What is the radius of the iron ball?