Consider an airfoil in a Mach 0.5 free stream. At a given point on the airfoil, the local Mach number is 0.86. Using the compressible flow tables at the back of this book, calculate the pressure coefficient at that point. Check your answer using the appropriate analytical equation from this chapter. [Note: This problem is analogous to an incompressible problem where the free stream velocity and the velocity at a point are given, and the pressure coefficient is calculated from Eq. (3.38). In an incompressible flow, the pressure coefficient at any point in the flow is a unique function of the local velocity at that point and the free stream velocity. In the present problem, we see that Mach number is the relevant property for a compressible flow—not velocity. The pressure coefficient for an in viscid compressible flow is a unique function of the local Mach number and the free stream Mach number.]