Real fluids are viscous because:

  1. they have no molecules
  2. gravity acts on them
  3. intermolecular forces (and molecular collisions) resist layers sliding past each other
  4. they are incompressible
Answer

C) intermolecular forces (and molecular collisions) resist layers sliding past each other

Layers drag on one another. SLO P-11-B-41 · Understanding

Physics MCQ · More Fluid Statics and Dynamics MCQs · Practise