Question

WHAT ARE THE ADVANTAGES & DISADVANTAGES OF FRICTION?? HOW CAN WE REDUCE FRICTION??

Answer 1

ADVANTAGES OF FRICTION
Friction plays a vital role in our daily life. Without friction we are handicap.
1. It is becomes difficult to walk on a slippery road due to low friction. When we move on ice, it     becomes difficult to walk due to low friction of ice.
2. We can not fix nail in the wood or wall if there is no friction. It is friction which holds the nail.
3. A horse can not pull a cart unless friction furnishes him a secure Foothold.
DISADVANTAGES OF FRICTION 
Despite the fact that the friction is very important in our daily life, it also has some disadvantages like:
1. The main disadvantage of friction is that it produces heat in various parts of machines. In this way     some useful energy is wasted as heat energy.
2. Due to friction we have to exert more power in machines.
3. It opposes the motion. 
4. Due to friction, noise is also produced in machines.
5. Due to friction, engines of automobiles consume more fuel which is a money loss. 
METHODS OF REDUCING FRICTION
There are a number of methods to reduce friction in which some are discussed here.
USE OF LUBRICANTS:
The parts of machines which are moving over one another must be properly lubricated by using oils and lubricants of suitable viscosity. 
USE OF GREASE:
Proper greasing between the sliding parts of machine reduces the friction.
USE OF BALL BEARING:
In machines where possible, sliding friction can be replaced by rolling friction by using ball bearings. 
DESIGN MODIFICATION:
Friction can be reduced by changing the design of fast moving objects. The front of vehicles and airplanes made oblong to minimize friction.

Answer 2

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Advantages of friction:-

It is because of friction that we can walk, drive, open doors, turn tap and write.Screw and nails do not slip of because of the friction between the wood and the metal surface of the screw .

Disadvantages of friction:-

Friction causes the moving parts in machinery and automobiles to heat up this results in wastage of energy and fuel. Fiction also causes wear and Tear of the moving parts .