$($a$)$ Define dynamic viscosity and give the mathematical formula for Newton's law of viscosity.

$($b$)$ How does kinematic viscosity differ from dynamic viscosity?

$($c$)$ Explain why viscosity is an important property in Fluid Mechanics.

$($d$)$ Name three classes of non$-$Newtonian fluids and explain how their viscosity is affected by factors other than temperature.

$($e$)$ What is the main difference between an 'ideal' fluid and a 'real' fluid?