Use the Shell Balance approach to solve the following problems: 1. A large airway is lined with a mucus layer of thickness, h, that has viscosity and density . Beating cilia on the airway wall beat up and down, acting to oppose the pull of gravity and "pump" the fluid upward. This process can be modeled by taking the fluid at the airway wall to be moving at V0. Assume airway mucus can be modeled as an incompressible, Newtonian fluid and that the system is at steady state with parallel flow. a. List the boundary conditions. b. Derive an expression for the shear stress in the mucus. c. Derive an expression for the velocity profile of the mucus. d. What value must V0 have in order for the net volumetric flow rate, Qv, of the liquid to be upward