Force school series 20

 Friction — The Force We Usually Try to Avoid

We learnt in school that friction is a force that opposes motion. It sounded like something inconvenient—something that makes machines wear out and objects harder to move.

But without friction, life as we know it would be impossible.

Try taking a step on a perfectly frictionless surface. Your foot would simply slide backwards. It is friction between your shoes and the ground that allows you to push against the Earth and move forward.

Friction lets us:

Walk and run

Hold objects

Write with a pencil

Stop a bicycle or car with brakes

Light a match

Grip a steering wheel

At the same time, friction can be troublesome. It produces heat, wears down moving parts and wastes some energy in machines. Engineers therefore try to reduce it with lubricants, bearings and smooth surfaces.

So friction is neither simply good nor bad.

We need enough friction when we want grip and as little as possible when we want things to move smoothly.

That little force we were taught to avoid in physics class is actually one of the reasons we can stand, walk, write and live normally.

Sometimes the force that resists us is precisely the force that allows us to move forward.