A Newtonian fluid flows in the space between two concentric tubes, as shown in Figure 2. M PU PL 2 Figure 2 Concentric tubes. [10 marks] a. Make a sketch of a volume element showing the relevant forces. b. Apply the momentum balance to an annular fluid shell of thickness Ar (use Shell balance or the equation of change to solve this problem) and: 1. Derive an expression for the velocity distribution in the annular space between two horizontals, concentric pipes. [20 marks] AP Show that the analysis of such a control volume leads to a (0) = r [20 marks]