normal stress

In physics and engineering, stress refers to the internal forces within a material that arise from external forces, uneven heating, or permanent deformation. It is calculated as force per unit area.1

There are different types of stress:
* Normal stress results from forces acting perpendicular to a material's cross-sectional area. This can be tensile stress (pulling apart) or compressive stress (pushing together). Hydrostatic pressure is a type of normal stress experienced when forces are perpendicular to all surfaces, like when an object is submerged in a fluid.1
* Shear stress arises from forces parallel to a material's cross-sectional area, tending to cause slippage or deformation.23

Stress is crucial for understanding a material's elastic, plastic, and fluid behaviors.1