A Non-Newtonian fluid is being sheared between two parallel plates. The top plate is moving at a velocity of 0.09 ft/sec and the bottom plate is stationary. The two plates are separated by a distance of 0.008 ft. The fluid is at 100F, with a density of 84.3 lbm/ft3, heat capacity of 0.0331 BTU/lbmF, surface tension of 2.5x10-3 lbf /inch, and kinematic viscosity of 0.256 ft2/sec. If the force on the fluid by the moving plate is 6 lbf and the area of contact is 0.05 ft2, please calculate the yield stress in this situation.