1) Consider a velocity field that is derived from the stream function 4 = 3axy-by, where a and b are non-zero constants. a) Compute the velocity components. b) Is this an incompressible velocity field? Justify this answer and all subsequent ones. c) Does this flow have any stagnation points? If so, find them. d) Determine a relationship between a and b for this flow to be irrotational. e) By two different methods, find the circulation I over the surface of a rectangle whose four corners are at the points (0,0), (2,0), (2,1) and (0,1). f) For a free stream velocity of 1 m/s and density of 1 kg/m find the lift per unit span.