Explain increasing and decreasing friction with suitable examples.

In our daily life, in many cases we increase or decrease friction for our own convenience. Some examples are given below:

Increasing friction:

• Soles of our shoes are grooved to provide the shoes better grip on the floor so that we can move safely. Similarly tyres of vehicles are treaded to increase friction to provide better grip.
• We increase friction by using brake pads in the brake system of bicycles and automobiles.
• Gymnasts apply some coarse substance on their hands to increase friction for better grip.
• Kabaddi players rub their hands with soil for a better grip of their opponents.
• Roads are made rough to prevent from slipping.
• Handle of cricket and tennis are made of rough materials to get better grip.

Decreasing friction:

In some situations, however, friction is undesirable and we would want to minimize it.

For example:

• A few drops of oil are poured on the hinges of a door; the door moves smoothly.
• A bicycle and motor mechanic uses grease between the parts of these machines to reduce friction.
• By polishing surfaces, sprinkling powder on carrom board, we reduce friction.

· Wheels and ball bearings are used in machines and vehicles to reduce friction.