Forces in action
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14. Friction

Friction is the force bodies can impart on each other when they’re in contact.

The friction forces are parallel to the contact surface and occur when…

• One body slide over the other, or…

• They cling together despite and external force.

It is a force that opposes the sliding of the surfaces.

Friction is a force that resists the motion of one object against another. Friction opposes the movement of objects.


Friction plays an important part in many everyday processes. For instance, when two objects rub together, friction causes some of the energy of motion to be converted into heat. This is why rubbing two sticks together will eventually produce a fire.

Check how to make a friction fire watching the video in the menu bar

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