2. Consider fully developed pipe flow of a highly viscous fluid with a viscosity model of =m. The flow is developed in the direction along the z-axis. The shear stress rz at the wall is known to be 0, where 0 has a positive value. The radius of the pipe is known to be R. Find the following items: a) Pressure gradient p/z. b) Shear stress r at r. c) Shear rate rz at r