What are Newtonian and Non-Newtonian fluids? Give examples of each.

Newtonian fluids have a constant viscosity that remains unchanged regardless of shear rate, following the relationship τ = μ(du/dy). Examples include water, air, light oils, and glycerin. Non-Newtonian fluids have viscosity that varies with shear rate or applied stress. Types include: shear-thinning (paint, blood, ketchup), shear-thickening (cornstarch in water), Bingham plastics (toothpaste, drilling mud), and viscoelastic fluids (polymer solutions). Understanding fluid behavior is crucial for pump selection and process design.