frictional force or friction is a force which opposes motion and acts in the opposite direction to the motion. it acts when two surfaces are in contact with eachother. you really need a very large force to overcome the friction between two things. The frictional force between an object and a surface can be measured using a spring balance.
frictional force exists between two surfaces in contact with each other. It is a force which slows down motion and acts in the opposite direction to the motion.
friction enables us to write and walk without slipping, treads in tyres and shoe soles help to increase friction for better grip.
the higher the speed of a vehicle, the greater its stopping speed.
friction can be a nuisance when it slows things down unncessarily, produces unwanted heat and causes wear and tear,which reduces the lifespan of machines!
friction can be reduced by the use of ball bearings and lubricants such as grease or oil, or by having streamlined shapes or cushions of air between surface.