Measurement of Pressure. An open U-tube manometer similar to Fig. 2.2-4a is being used to measure the absolute pressure p, in a vessel containing air. The pressure p is atmospheric pressure, which is 754 mm Hg. The liquid in the manometer is water having a density of 1000 kg/m. Assume that the density pa is 1.30 kg/m and that the distance Z is very small. The reading R is 0.415 m. Calculate p, in psia and kPa. Pa (a) FIGURE 2.2-4. fluid B PB fluid A PA