Q3) Air flows through a variable area duct. At section 1, area 20 cm³, P-300 kPa, velocity-122.5 m/s and density is 1.75 kg/m'. At section 2, the area is exactly the same, but the density is much lower, density equal to 0.266 kg/m³, temperature-281 K. There is no transfer of work or heat. Assume one-dimension steady flow. Find: a) Mass flow rate at section 2 b) Velocity at section 2 c) Pressure at section 2 d) Change in entropy between section 2 and section 1