Question 1: Consider NACA23012 airfoil. In low-speed flow, the zero-lift angle of attack -1.1°. When the angle of attack a = 2°, (a) for low-speed flow, from the results of thin airfoil theory, calculate the lift coefficient and the aerodynamic center, and also give the drag coefficient; (b) for subsonic flow M = 0.75, using Prandtl- Glauert compressibility correction, calculate the lift coefficient and the drag coefficient.