A fluid with viscosity $\eta$ flows through a horizontal pipe of radius $r$ and length $L$ The press

Question

A fluid with viscosity $\eta$ flows through a horizontal pipe of radius $r$ and length $L$ The pressure difference between the two ends of the pipe is $P$. What is the flow rate of the fluid?

Professor PC Thomas Classes · Answer

Poiseuille's law gives flow rate $Q = \frac{\pi r^4 P}{8 \eta L}$.