Friction

Friction: a force that acts parallel to the interface of two surfaces that are in contact, and opposes their relative motion

Coefficient of friction: a measure of the amount of friction existing between two surfaces

The magnitude of the coefficient of friction depends on the materials in contact

E.g. steel on ice (ice skating) has a low coefficient of friction

E.g. rubber on the ground (running) has a high coefficient of friction

The greater the interaction between the molecules of the interacting surfaces, the greater the size of the coefficient of friction.

Dry and rough surfaces = high friction

Smooth and wet surfaces = low friction

Mass (kg) x 9.81 to give you force (N)

Related to newtons first law

Static Friction: the force acting between two surfaces that are not moving relative to each other (scalar)

When a force is applied to attempt to move a stationary object over another surface (static friction)

Dynamic Friction: the forces of two objects that are sliding against each other (the force it takes to keep a moving object moving)

When the force applied to a stationary object is sufficient to overcome static friction, the object will begin to move (dynamic friction)

Coefficient of dynamic friction is usually lower than the coefficient of static friction

Maximise	Minimise
Playing surface E.g. changing the playing surface to tarmac/astroturf/synthetic track/dry court Increase friction on the ground, so they can change directions more easily Footwear E.g. wearing studs/spikes Equipment E.g. waxing a surfboard/wear gloves in gold/chalking Temperature E.g. warming Increase the temperature of tyres in F1	Playing surface E.g. changing the playing surface to a wet/waxed floor Footwear E.g. wearing ice skates Manipulation of equipment E.g. add lubricants to chains/wax floors