A perfect gas of molecular weight M = 20 and specific heat ratio = 1.2 expands

A perfect gas of molecular weight M = 20 and specific heat ratio γ = 1.2 expands adiabatically in steady flow from a pressure of 6 MPa, a temperature of 3000 K, and a velocity of 200 m/s to a final pressure of 0.101 MPa.
a. If the final temperature is 1800 K and the final velocity is negligible, how much work per unit mass of gas has been done during the expansion?
b. For any adiabatic expansion from the same initial conditions to the same final pressure, is it possible for the final temperature to be as low as 450 K? Consider the implication for an adiabatic process and use the link between entropy, temperature, and pressure indicated , remembering that (purely for ease of calculation) γ is taken to be
constant in this problem.
c. If no work is done on or by the gas during the process of expansion to the final pressure of 0.101 MPa, what is the maximum possible final velocity? In this case, how high would thefinal temperature be?