3. (35 points). The gage pressure of the air in the tank shown in Figure 3 is

measured to be 90,000 Pa, and the density of water is 1000 kg/m³.

(a) Determine the differential height h of the mercury column.

(b) If you replace the water with a higher density liquid, does the differ-

ential height of the mercury column increase or decrease?

(c) If you replace the oil with a higher density liquid, does the differential

height of the mercury column increase or decrease?

Pgage 90,000 Pa

=

air

water

80 cm

h

Patm

oil

SG = 0.72

mercury

SG = 13.6

35 cm

Figure 3: Three fluid manometer.