* Heat generation: Friction generates heat. This is why brake pads and rotors become hot when you apply the brakes.

* Wear and tear: Friction can cause surfaces to wear and tear over time. This is why tyres and brake pads need to be replaced periodically.

* Motion resistance: Friction resists motion. This is why it can be difficult to push or pull objects that are heavy or have a lot of surface area.

* Sound production: Friction can produce sound. This is why you hear a squeaking noise when you rub two pieces of metal together.