4. Let's consider the steady, planar, incompressible, viscous flow between two concentric cylinders. Such a configuration is used in shear rheometers to measure the viscosity of low viscosity samples. In this configuration, the inner cylinder at radius, R; is rotating with an angular velocity w. The outer cylinder is stationary and has radius R. Assume that the cylinders are large, such that no flow in the axis of rotation is expected. Ignore the effect of gravity, and the density of the fluid is given by p. (a) Determine the velocity distribution in the region between both cylinders. (b) Determine the stress on the inner cylinder, and the torque, i.e. r x, required to spin the cylinder, given the viscosity of the fluid, . (e) Determine the difference in the pressure between the outer surface of the inner cylinder and the inner surface of the outer cylinder