1. A certain nozzle expands a gas under isentropic conditions. Its chamber or nozzle entry velocity equals 90 m/sec, its final velocity 1500 m/sec. What is the change in enthalpy of the gas? What percentage of error is introduced if the initial velocity is neglected?
2. Nitrogen at 500? C (k = 1.38, molecular mass is 28.00) flows at a Mach number of 2.73. What are its actual and its acoustic velocity?