17. Air enters the turbine section of a jet engine at a temperature of 1,500 C and leaves at 500 C. Compute the change in specific enthalpy (kJ/kg) through the turbine in four different ways: a. assuming constant specific heat evaluated at the entering temperature using the polynomial expressions in Table 3s b. assuming constant specific heat evaluated at the mean temperature using Table 4s c. integrating the polynomial function in Table 3s to account for variable specific heat d. using the h values tabulated in Table 5s. Compare your results for methods a, b, and c with those of method d. Do the h values in Table 5s take variable specific heat into account?