A hydrometer is a device for indicating the specific gravity of liquids. Figure shows the design for a hydrometer in which the bottom part is a hollow cylinder with a 1.00-in diameter, and the top is a tube with a 0.25-in diameter. The empty hydrometer weighs 0.020 lb. What weight of steel balls should be added to make the hydrometer float in the position shown in fresh water? (Note that this is for a specific gravity of 1.00.)
For the hydrometer designed in above problem, what will be the specific gravity of the fluid in which the hydrometer would float at the top mark?