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Three Cs Part Two - Centre of Pressure and Centre of Force

Two very important concepts to understand in biomechanics are Centre of Pressure and Centre of Force.
These are often used interchangeably but are actually different, mostly though, by convention, it is CoP that is used when considering how normal forces act over an area. Normal force means that force perpendicular to the surface of interest. When 2 objects act on each other with force then there will always be an interface that has some area and the forces acting over that area are called pressure. Pressure if Force divided by area and the unit of pressure is the Pascal, however 1 pascal is very small at 1N/m^2 or 100grams spread over 1million sq millimeters = 0.00001 grams / mm^2. So it is common to use kilopascals (1000 pascals) or KPa as the standard unit of pressure.
Go here for a PPT presentation on CoF Vs CoP

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