a whirlpool is modeled as the combination of a free and a forced vortex. the maximum velocity in the whirlpool is 10 m/s, and the radius at the juncture of the free and the forced vortex is 10m. the pressure is atmospheric (gage pressure=0) at the free surface. plot the shape of the water surface from the center to a radius of 50m. the elevation is zero for the vortex center, where the velocity is zero.