What ways do you know to reduce friction?

Hint: Friction opposes the motion of a body so various methods are used to reduce friction over a surface. Some of the ways of reducing friction are by polishing, lubrication, streamlining or by using ball bearings. These methods can reduce frictional losses up to a large extent.

Complete step by step answer:
Friction is an opposing force that acts on a body when it moves on a surface. It develops at the surface of contact of two bodies and opposes their relative motion. Since it opposes the relative motion between two bodies extra energy must be spent. It also causes wear and tear to the machinery and produces heat which further causes damage to the machinery.

There are several methods of reducing friction between two surfaces, some of them are discussed here:
1. By polishing the surface of an object, it becomes smooth and friction can be reduced
2. By using lubricants like oil, grease etc, that fill up the irregularities of the surfaces also makes them smooth and reduces friction.
3. It can also be reduced by using materials that have low coefficients of friction.
4. Friction can be reduced by streamlining the shape of the body that is making them sharp in front. For e.g. Aeroplanes, jets, cars etc are given streamline shape.
5. By using ball bearings made of steel balls, the sliding friction can be converted into rolling friction, which is much less than sliding friction.

Note: Frictional force between two surfaces converts kinetic energy into thermal energy .Through friction causes a lot of problems it's also very necessary as it has its applications in our day to day life. Friction helps in walking action, applying brakes in vehicles, in writing etc therefore it is called a necessary evil.