friction as a friend ;
1)we can walk or run because of friction between feet and floor .to walk gently on the road,the sole of our shoes is grooved,because to produce shoes better grip on the floor.the tyres of cars and trucks are threaded .
2)gymnasts apply some coarse substances on their hands to increase friction for better grip.
3)fixing a nail on a wall or in a wooden block is possible because of friction.
4)lightening a match stick and sewing of clothes are some other useful applications of friction
friction as a foe:
1)friction is undesirable in all machinary.
2)friction is responsible for overwhelming & wearing out of moving parts.
3)machine parts that come in contact with one another wear out because of friction.similarly the soles of our shoes wear out because of friction