Friction is a necessary evil. Explain.

Explanation

Friction is a necessary evil because it has advantages as well as disadvantages. In other words, we cannot survive without this undesirable force.
Disadvantages i) Larger amount of energy of moving object is wasted in form of heat energy to overcome the friction.
ii) Force of friction restricts the speed of moving vehicles.
iii) Efficiency of machine decreases due to friction.
iv) Friction causes wear and tear in moving parts of a machine.
Advantages i) We cannot walk on the surface in the absence of friction.
ii) Friction helps us to write on paper with pen.
iii) In absence of friction, vehicles will skid off of the road.
iv) Moving belts remain on the rim of wheels because of friction.