Question: Air flows from a large tank through a well-insulated 12-mm-diameter pipe. If the air enters the pipe at Mach 0.2 and leaves at Mach 0.6, find the length of the pipe. Assume a mean friction factor of 0.005. How much longer must the pipe be if the exit Mach number is 1? If the pipe is 75 cm longer than this latter value and if the same conditions exist in the supply chamber, what reduction in the flow rate will occur?