2 of 2 iscosity, the Stress-Strain Rate relationship (10 points) The cone and plate viscometer shown is a common instrument used to characterize the viscosity of non-newtonian fluids. It consists of a flat plate and a rotating cone with a very small angle (0 < 0.5° typically). The apex of the cone just touches the plate surface and the liquid to be tested fills the narrow gap formed by the cone and the plate. a) Derive an expression for the shear rate in the liquid that fills the gap in terms of the geometry of the system. b) Evaluate the toque on the driven cone in terms of the shear stress and the geometry of the system. 3 R