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Q9. A tank containing lubricating oil has two sharp edge orifice outlets on one side.

The upper orifice has a diameter of 20 mm and its centre is located 1.275 m below the surface of the oil. The centre of the lower orifice is located 2.8 m below the surface.

The oil level in the tank is maintained constant and the mass flow rate through each nozzle is the same.

Calculate EACH of the following:

(a) the mass of oil flowing into the tank per hour; (8)

(b) the diameter of the lower orifice. (8)

Note: for oil ρ = 850 kg/m³

for the upper orifice C_v = 0.97, C_c = 0.67

for the lower orifice C_v = 0.91, C_c = 0.72