Question

Part 1. Water in the reservoir is used to control the water pressure in the pipe at A. If h = 200 mm, determine this pressure when the mercury is at the elevation shown. Take p_Hg = 13 550 kg/m³. Neglect the diameter of the pipe.

Part 2. The two tanks A and B are connected using a manometer. If waste oil is poured into tank A to a depth of h = 0.6 m, determine the pressure of the entrapped air in tank B. Air is also trapped in line CD as shown. Take p_o = 900 kg/m³ p_W = 1000 kg/m³.

Answer 1

1)

Referring to Fig. A with h = 0.2 m, the manometer rule gives

$P_{A} + \rho_ {w}gh_{AB} – \rho_{ Hg}gh_{BC} – \rho _{w}g(h_{CD}+h_{DE})=P_E,$

​$P_A = 18.2~\text {kPa}.$

2)

Referring to Fig. B, the manometer rule gives

$P_{A} – \rho _{o}gh_{AE} + \rho _{w}gh_{CE} + \rho _{w}gh_{BD} = P_{B},$

$P_B=20.8~\text{kPa}.$