A hydrometer of a given weight will sink when placed in a fluid, and the amount it sinks is based on the fluid density. The hydrometer shown in the figure below has a mass, m, of 0.09 kg, and the cross-sectional area, Acs, of its stem is 290 mm. The hydrometer is neutrally buoyant when placed in a fluid with S.G. = 1.0. a. Will the hydrometer rise or sink when placed in a fluid of S.G. 0.9? Calculate by how much (in mm). Be sure to draw a free body diagram and a force balance. b. The highest gradation mark on the stem of the hydrometer is 15 cm above the lowest. If the smallest S.G. the hydrometer can measure is 0.7, what is greatest S.G. that this hydrometer can measure? (Hint: Is the S.G. = 0.7 reading at the top or bottom of the hydrometer?) Hydrometer- Fluid surface Figure 1. A hydrometer floating in a fluid.