Newton’s law of viscosity is given by
Ƭ = µ du/dy
Ƭ = shear stress.
µ = absolute or dynamic viscosity.
du/dy = velocity gradient.
Newtonian fluids: Fluids which follow this law are known as Newtonian fluids.
Example of Newtonian fluids are Air, water etc.
But non Newtonian fluids are tar, paste, blood, glycerin etc.