Helium at \(68{ }^{\circ} \mathrm{F}\) and 14.7 psia in a large tank flows steadily and isentropically through a converging nozzle to a receiver pipe. The cross-sectional area of the throat of the converging passage is \(0.05 \mathrm{ft}^{2}\). Determine the mass flowrate through the duct if the receiver pressure is

(a) \(10 \mathrm{psia}\),

(b) 5 psia. 

Sketch temperatureentropy diagrams for situations (a) and (b).