The hydrodynamic friction is associated with the phenomena when a complete film of lubricant exists between the two bearing surfaces.

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

During normal engine operation there is almost no metallic contact except between the compression piston ring and cylinder walls.

During starting of the engine, the journal bearings operate in ____________ friction.

The ____________ friction is due to rolling motion between the two surfaces.

Ball and roller bearings and tappet rollers are subjected to rolling friction.

Rolling friction coefficient is ____________ than journal bearing friction coefficient during starting and initial running of engine.

A circular cylindrical shaft called journal rotates against a cylindrical surface called the bearing.

Total friction is negligible compared to rolling friction.

The mechanical friction ___________ with increase in speed.