Air(Cp =1.05kJ/kg-K, =(1.38) at 3 bar and 500K flows with a velocity of 250m/s in a 30cm ID duct available. a. Calculate the mass flow

Air(Cp =1.05kJ/kg-K, γ=(1.38) at 3 bar and 500K flows with a velocity of 250m/s in a 30cm ID duct available.
a. Calculate the mass flow rate,
b. Stagnation temperature,
c. Mach number,
d. Stagnation pressure values assuming the flow as compressible.
Assumption: Air is 79% N2 and 21% O2