The velocity potential for the flow around a rotating cylinder is given by _ is the circulation strength, __ the radius of the cylinder, and ___ the velocity of the parallel flow. (a) Derive the equations for the velocity vector in Cartesian and polar coordinates. (b) Compute the location of the stagnation points as a function of the position angle __ for circulation strength values _ _ 4_______. (c) What happens to the stagnation point if _ > 4_______? (d) Compute the resultant pressure force acting on the cylinder as a function of ___, __, and _. This is best done in polar coordinates.