A biomedical device start-up company is developing a liquid drug injection device. The device uses compressed air to drive the plunger in a piston-cylinder assembly that will push the drug (viscosity and density similar to water at 10 °C) through the hypodermic needle (inside diameter 0.25 mm and length 50 mm). If the flow must remain laminar in the hypodermic needle, determine:
a. the maximum flow possible (in cm3/s)
b. the required air pressure for the maximum flow if the pressure at the end of the needle must be 105 kPa (in kPa). (Assume fully developed flow.)