Air enters a 5-cm-diameter pipe at p1 = 200 kPa and T1 = 350 kPa. The downstream receiver pressure is 74 kPa and the friction factor is 0.02. If the exit is choked, what is
(a) The length of the pipe, and
(b) The mass flow?
(c) If p1, T1 and preceiver stay the same, what pipe length will cause the mass flow to increase by 50% over (b) Hint: In (c) the exit pressure does not equal receiver pressure.