Question

In hydrodynamic friction, the friction force does not depends on the lubricant viscosity.

(a) True

(b) False

I have been asked this question in an internship interview.

My question is taken from Mechanical Friction in portion Engine Friction and Lubrication of IC Engine

Answer 1

The correct answer is:

(b) False

In hydrodynamic friction, the friction force does depend on the lubricant viscosity. Higher viscosity provides a thicker, more stable lubricant film, which can increase resistance to flow (and thus friction), while lower viscosity results in less resistance. The viscosity must be carefully selected to balance frictional resistance and adequate separation of bearing surfaces.