Thermodynamics

44 | Thermodynamics1–66 Consider a 1.8-m-tall man standing vertically in waterand completely submerged in a pool. Determine the differencebetween the pressures acting at the head and at the toesof this man, in kPa.Air2 in1–67 Consider a U-tube whose arms are open to the atmosphere.Now water is poured into the U-tube from one arm,and light oil (r 790 kg/m 3 ) from the other. One arm contains70-cm-high water, while the other arm contains bothfluids with an oil-to-water height ratio of 4. Determine theheight of each fluid in that arm.NaturalGas10 in6 in25 inMercurySG = 13.6Water70 cmWaterFIGURE P1–67OilFIGURE P1–71E1–72E Repeat Prob. 1–71E by replacing air by oil with aspecific gravity of 0.69.1–73 The gage pressure of the air in the tank shown in Fig.P1–73 is measured to be 80 kPa. Determine the differentialheight h of the mercury column.1–68 The hydraulic lift in a car repair shop has an outputdiameter of 30 cm and is to lift cars up to 2000 kg. Determinethe fluid gage pressure that must be maintained in thereservoir.80 kPa75 cmOilSG = 0.721–69 Freshwater and seawater flowing in parallel horizontalpipelines are connected to each other by a double U-tubemanometer, as shown in Fig. P1–69. Determine the pressuredifference between the two pipelines. Take the density of seawaterat that location to be r 1035 kg/m 3 . Can the air columnbe ignored in the analysis?Air30 cmWaterhMercurySG = 13.6AirFIGURE P1–73Freshwater60 cm70 cm40 cmSeawater1–74 Repeat Prob. 1–73 for a gage pressure of 40 kPa.1–75 The top part of a water tank is divided into two compartments,as shown in Fig. P1–75. Now a fluid with an10 cmMercury80 cmUnknownliquidFIGURE P1–691–70 Repeat Prob. 1–69 by replacing the air with oil whosespecific gravity is 0.72.1–71E The pressure in a natural gas pipeline is measured bythe manometer shown in Fig. P1–71E with one of the armsopen to the atmosphere where the local atmospheric pressureis 14.2 psia. Determine the absolute pressure in the pipeline.50 cmWATERFIGURE P1–7595 cm