4. A two-dimensional incompressible source flow of strength A=2 is placed at the origin (0,0) of a Cartesian coordinate (x-y) system. A flow field described by the stream function = xy, is superimposed on this source flow. By considering the flow pattern in the region - 0x and y>0, (a) Find the location of the stagnation point (10%)) (b) Derive the equation for the body shape. (10%) (c) If the freestream velocity is 1 m/s, find the pressures coefficient (Cp) at the point on the body surface with its coordinate =/4 (10%) Hint: The stream function of a source flow with strength A placed at the origin (0,0) is -1 az (tanx) = 1 & tan- ( ) == 1+x = 0 2TT