16. The law of Hagen-Poiseuille describes the pressure drop in tubing with a flowing fluid. Law of Hagen-Poiseuille 8nL Ap = V r4 Viscosity, and the digit 8 are constant and can be cancelled, the following approximated equation remains: Ap a) Calculate the pressure drop for given volume flow of 5 l/min, a tubing length of 2 m and a tubing radius of 0.5 m. b) Describe the exact change of the pressure drop if the radius is reduced by 50 %.