Sometimes, friction is useful to us
Due to lack of friction,there may be risk of accident
We may need to increase friction to prevent slipping and function properly
This is done by various methods as shown below
Example 1
Sole of shoe is grooved(rough). This increase friction and prevents us from slipping
Example 2
Tyres are treaded so that it does not skid and stop immediately when brakes are applied
Example 3
Studs (Football shoes) have spikes in it
This also helps in increases friction
When the footballer runs,it prevents him from slipping
Example 4
Kabaddi Player wipe their hand with dry sand
This is done to increase friction in hands of player
So their hands do not skid when they touch other player's sweaty hands and legs
Example 5
Bowlers wipe ball with dry cloth
When there is dew,bowlers are not able to spin the ball because ball is wet and there is less friction and they are not able to hold it properly.
So they wipe ball with dry cloth to increase friction and make ball spin
