Topic: Machine Design
Starting friction is low in
- A. Hydrostatic lubrication
- B. Hydrodynamic lubrication
- C. Mixed lubrication
- D. Boundary lubrication
Answer: A. Hydrostatic lubrication
Explanation: Hydrostatic lubrication involves supplying a pressurized fluid from an external pump to keep the mating surfaces completely separated, even before relative motion begins. This ensures that the starting friction is exceptionally low compared to hydrodynamic lubrication, which relies on motion to build up a fluid film.