(a) Since the flow rate is proportional to the pressure difference, show that Poiseuille’s law can be written in the form ΔP = IR, where I is the volume flow rate and R is a constant of proportionality called the fluid flow resistance. (Written this way, Poiseuille’s law is analogous to Ohm’s law for electric current to be studied in Chapter 18: ΔV = IR, where ΔV is the potential drop across a conductor, I is the electric current flowing through the conductor, and R is the electrical resistance of the conductor.) 

(b) Find R in terms of the viscosity of the fluid and the length and radius of the pipe.