Pressure

Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the ambient pressure.

Definition

Pressure is the amount of force applied at right angles to the surface of an object per unit area. The symbol for it is p or P. The IUPAC recommendation for pressure is a lower-case p.

Units

In the International System of Units (SI), the unit of pressure is the pascal (Pa), equal to one newton per square metre (N/m², or kg·m−1·s−2). This name for the unit was added in 1971; before that, pressure in SI was expressed in units such as N/m².

Scalar nature

Pressure is a scalar quantity. It relates the vector surface element (a vector normal to the surface) with the normal force acting on it. The pressure is the scalar proportionality constant that relates the two normal vectors:

The minus sign comes from the fact that the force is considered towards the surface element, while the normal vector points outward.

Applications

Pressure is a critical element in various fields such as physics, engineering, and medicine. It plays a significant role in fluid dynamics and thermodynamics, among other scientific and practical areas.

See also

• Atmospheric pressure
• Fluid dynamics
• Hydrostatic pressure
• Pascal's law
• Pressure measurement
• Pressure sensor
• Pressure system
• Surface tension

References

Pressure Resources
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