Pressure
Definition
How concentrated a force is over an area. The same push hurts more through a sharp pin than through a flat palm, because the pin concentrates the force on a tiny area.
Symbol: · Unit: pascal (Pa)
Technical definition
Force applied perpendicular to a surface per unit area: P = F/A. The SI unit is the pascal (Pa = N/m²). In fluids at rest, pressure acts equally in all directions and increases with depth.
Example
A 60 kg person standing on one stiletto heel (area about 1 cm²) exerts roughly 5.9 million pascals — over 50 times atmospheric pressure — which is why heels dent soft floors while flat shoes do not.
Pressure is not the same as force. A large force spread over a large area can mean low pressure, while a small force on a tiny area can mean enormous pressure. Whenever a problem mentions 'sharp,' 'pointed,' or 'concentrated,' think pressure, not just force.