Question

Mention the methods used to decrease friction.

Answer 1

Hint: Friction is a resistive force which leads to dissipation of energy. In the case of solids, it can be reduced by removing various imperfections on the surface of two bodies sliding over each other in case of solids. In case of fluids, streamlining the shape of bodies helps in reducing friction.

Complete Step-by-Step solution:
Friction is a resisting force which comes into action when two bodies slide over each other. In other words, we can say that friction opposes the motion of one body over another.
Underlying working principle of friction is that when two bodies come in contact with each other and try to slide over each other, their surface may not be smooth and may have bumps and uneven surfaces. This leads to jerky motion which is characterized as friction.
Friction is a dissipative force which means that work is done and energy is expended when two bodies slide over one another.
Friction can be seen in action everywhere around us but this phenomena may or may not be desirable depending on what we are talking about. For instance in mechanical devices when different parts slide over one another, friction comes into play and can lead to drastic consequences if there is a lot of friction between various parts.
So, there are certain ways by which we can decrease the amount of friction in a system.
1. Smoothing the surfaces: By polishing a surface, we can remove excessive dents or ridges which increase the amount of friction.
2. Lubrication: Lubricants have oily texture which helps in reducing friction. They fill up gaps and ridges thereby making sliding smoother.
3. Streamlining: Friction can be reduced by making the objects shape streamline which need to move in fluids like liquid and air. E.g. Airplanes have streamlined bodies to reduce friction due to the atmosphere.
4. Rolling motion: Friction is far less in the case of bodies rolling over each other than bodies sliding over each other.

Additional Information:
All the forces that we come across can be derived from the four fundamental forces of nature: Gravitational force, Electromagnetic force, Strong and weak nuclear force. Friction comes into action due to the electromagnetic force of nature. It is electromagnetic force between the charged particles in the atoms of the bodies that results in frictional force.

Note: The friction is not always an undesirable phenomenon but for industrial applications, it is better to reduce friction as it leads to loss of energy. The mentioned methods to reduce friction are one of the most commonly used and all of them are important to remember from examination point of view, especially point 3 which is very important in the field of fluid dynamics.