a) By aid of a diagram, explain how the surface of fluid particles rotates? (2 marks) b) The pressure coefficient at a certain point on a two-dimensional airfoil in a very low Mach number air flow is found to be -0.5. Using linearized theory, estimate the pressure coefficients that would exist at the same point on this airfoil in flows at Mach numbers of 0.5 and 0.8. (4 marks) c) A thin airfoil can be approximated as a flat plate. The airfoil is set at an angle of 10 to an air flow with Mach 3, a temperature of -50C, and a pressure of 50 kPa. Using linearized theory, find the pressures on the upper and lower surfaces of this wing