A viscometer is built from a conical pointed shaft that turns in a conical bearing. As shown. The gap between shaft and bearing is filled with a sample of the test oil. Obtain an algebraic expression for the viscosity ? of the oil as a function of viscometer geometry (H. a, and ?), turning speed ?. and applied torque T. For the data given. Find by referring to Figure Al in Appendix A, the type of oil for which the applied torque is 0.325 N. m. The oil is at 20t. Hint: First obtain an expression for the shear stress on the surface of the conical shaft as a function of z.

a = 0.2 mm H = 25 mm P2.73 w = 75 rev/s - 8 = 30