Whenever you were trying to reach high speeds or conduct exact experiments where friction would slow something down or cause heat. For example, friction is extreamly "unuseful" when spaceshuttles are re-entering the atmosphere because the friction of the spacecraft and the air create incredibly height temperatures. Special heat plates were invented to absorb this heat. If they fail, like in the re-entry of the Columbia Space Shuttle, the shuttle will be completely destroyed.
there is friction in your cars brake system and without that frictiuon there your car would roll away whenever it was on a hill so this is a good example of when friction is useful.
Brakes are meant to have a lot of friction and it's useful.
A fire drill is a drill that uses friction to start a fire. It can be very useful when trying to survive in the wilderness Without friction everything would be so slippery that we would have trouble walking or holding anything. Vehicle brakes work thanks to friction between the brake and the wheel. Without that, or the friction on the road, cars would never stop. The list goes on... and on... and on.
No Friction Runes Computers
the friction from pushing the hull through the water is not useful as long as you're travelling.
It can be useful when a ball is catching
how does friction help car tyres?
Sandpaper is high in friction but is not considered useful in terms of being helpful in a general sense.
stopping cars Friction is useful to start a fire with sticks.
It is useful
Friction is useful when you are trying to stop a car, but not useful in the pistons of a car's engine (It makes them less efficient).
No... It depends on what you would use it for... TROLOLOLOLO friction is useful to almost anything we do. We could not run, walk, stay on a balance beam, hold on to rings or a horizontal bar. We couldn't do floor exercises without friction on the mat. If you swing on parallel bars you need friction to hold onto the bars.