“A force that acts parallel to the interface of two surfaces that are in contact, and opposes their relative motion”

nature of footwear and the surfaces , reaction forces - e.g weight

spikes / studs - increase grip

Law of motion/acceleration - force is equal to mass multiplied by acceleration - the acceleration of an object is directly proportional to the net force acting

when two or more objects come into contact with (exert forces on) each other during a short period of time.

the frictional force between surfaces that are moving relative to each other

refers to the force acting between two surfaces that are not moving relative to each other

Law of inertia - an object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction, unless acted upon by an

f = coefficient friction N (or R)

relative velocity after collision / relative velocity before collision

Law of reaction - for every action there is an equal and opposite reaction

New tennis / table tennis balls in matches; table tennis balls / basketball checked and must bounce to a certain height; golf club / baseball bats limit CoR

Technique and sports equipment design