What is friction?

• Friction can be defined as the force that opposes motion.

• It occurs when two solid surfaces rub together.

• To make an object move, you must apply force to it. This motion force has to overcome the force of friction, otherwise it will not move.

• Friction can be affected by a range of factors.

What factors affect friction?

• Materials: some materials will create less friction due to their surface. A rough surface will create more friction than a smoother surface.

• Mass: things that are heavy will be subject to more friction than things that are light.

• Surface area: if the area of the two objects rubbing together is large, it will create more friction.

• Liquids: the addition of a liquid can reduce friction by making the surface slippery. Dry surfaces tend to have more friction.

Yes! There are two other kinds of friction you should know about:

●Air resistance is when a solid object moves through air or gases.

●Similarly, water resistance is when a solid object moves through water or liquids.

We experience these everyday – when you move you are constantly overcoming air resistance.

​Are there different kinds of friction?

How can we use friction to our benefit?

Friction has many practical uses in the world.

​Some uses include:

●braking systems in vehicles;

●stringed musical instruments;

●door stops;

writing.

​​Uses of Friction

​●Friction makes movement harder.

●Friction wastes energy.

●Friction creates heat.

Friction wears things out.

Problems Friction Can Cause