## Sunday, December 6, 2015

### Friction can only be Minimized but cannot be reduced to Zero

Friction is a force which opposes relative motion. Friction exists between every two solid surfaces that are in contact. When we try to move one body over the other body, frictional force opposed this motion. Each surface has its own irregularities. Sometimes we may not be able to see that irregularities. But if you put them under a powerful microscope we can see that irregularities. When one body is kept over the other body, this irregularities get interlocked with each other and this opposes the further motion of one body with respect to the another body. Friction comes into action only when we try to move your body. If you don’t try to move your body, there is no one opposing the interlocking and hence there is no frictional force.

Because of the friction, there is Wear and tear of mechanical parts of the machines. We need energy resources like petrol and diesel to overcome the road friction between the tires and the road continuously. Hence lots of energy resources are wasted in real life in overcoming friction.

Anyway we cannot survive without friction. We cannot hold a glass, we cannot sit, we cannot hold a pen and what not, we cannot touch one body with the other body and hold anything because there is no interlocking between the two surfaces. Therefore without friction we cannot imagine our life and it is going to be disastrous. That’s why people call friction as a necessary evil. So we need to have the friction to survive and having a large amount of the friction is killing a lot of the energy resources.

Therefore the best thing that we can do is minimising the friction therefore we can save certain amount of energy. This can be done simply by reducing the irregular surfaces of the body. Once we reduce the irregular surfaces, the interlocking also will be less and hence frictional force also can be reduced. Therefore it is very clear that if we want to reduce the friction, we shall reduce the interlocking.

Polishing the surfaces is one of the simple method that we can follow to reduce the friction. It is obvious that when we polish the surface, the irregularities will decrease and hence automatically the interlocking also decreases. Therefore the opposition to the relative motion which is frictional force is less and hence we can more the body easily. Anyway if you keep on polishing the surface of a body, the surfaces becomes very smooth and surprisingly friction is not going to become zero.

It is simply because when the surfaces comes too close to each other, the molecules of this two surfaces also comes close to each other and between them there is always a force of attraction. If this molecules belongs to different types, the force of attraction is called adhesive force of attraction and the molecules belongs to the same type of the material, the force of attraction is called a cohesive force of attraction. Anyway it is always attractive. Hence molecular force of attraction again starts opposing the relative motion. That’s why a friction can only be minimised but cannot be reduced to zero.

Using ball bearings, lubricants and streamlining are the other methods to reduce the friction.

Find the video lesson of this friction can be only be minimized here below.

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