Question: The pressure, temperature, and Mach number at the entrance to a duct through which air is flowing are 250 kPa, 26°C, and 1.4, respectively. At some other point in the duct, the Mach number is found to be 2.5. Assuming isentropic flow, find the temperature, velocity, and pressure at the second section. Also, find the mass flow rate through the duct per square meter at the second section.