Question

give examples to show that friction is both and foe ​

Answer 1

Examples of friction as friend:

we are able to write because of friction between pen and the paper surface

we are able to walk because of friction between our sole and the ground

Examples of friction as foe :

Tear of sole of the shoes is due to friction

Machines get heated up and produce noise due to friction

Answer 2

Advantages of friction

• We can hold onto things and grip them easier
• We will be able to walk or drive on roads normally without slipping too much
• Blackboard and whiteboard will not exist without friction, as it is the friction between the blackboard/whiteboard and the chalk-dust/marker-ink that keeps the writing intact.
• An object in motion will not be able to stop or change direction if there is no friction to oppose the motion.
• A nail cannot be fixed onto a wall if there is no friction to hold the nail in place, it will slip out easily.
• Friction aids in the construction of buildings.

Disadvantages of friction

• Friction produces heat. This heat causes wear and tear in machine parts. This is called 'overheating'.
• The heat liberated from friction also causes wastage of mechanical energy.