일반물리학 1 — Fluids: Problem 28

28 A flotation device is in the shape of a right cylinder, with a height of 0.650 m and a face area of 4.00 m² on top and bottom, and its density is 0.300 times that of fresh water. It is initially held fully submerged in fresh water, with its top face at the water surface. Then it is allowed to ascend gradually until it begins to float. How much work does the buoyant force do on the device during the ascent?