3.10 Methods to Reduce Friction
The following methods are used to reduce friction:
- Polishing surfaces: The parts which slide against each other are highly polished.
- Using lubricants: Since the friction of liquids is less than that of solid surfaces, oil or grease is applied between the moving parts of machinery.
- Using ball bearings: As rolling friction is much less than sliding friction, sliding friction is converted into rolling friction by the use of ball bearings in machines and wheels under heavy objects.
- Streamlining: Frictional force does not act only among solids. High-speed vehicles, aeroplanes, and ships also face friction while moving through air or water. If the front of a vehicle is flat, it faces more resistance from air or water. Therefore, the bodies moving through air or water are streamlined to minimize friction. The air passes smoothly over the slanting surface of the vehicle. This type of flow of air is known as streamline flow.