Helium enters a 100 mm - 1D pipe from a converging diverging nozzle at M = 1.30, P = 14kPa, T = 225 K. Estimate for an isothermal flow (i) the maximum length of pipe for no choking, (ii) the downstream conditions, and (iii) the length from the exit to the section where M = 1.0, f = 0.016