Which of the following is not one of the five types of stress?

The correct choice not classified as one of the five types of stress is friction. In the context of mechanics and material science, stress usually refers to the internal forces that develop within a material when it is subjected to external loads. The primary types of stress typically recognized in this field are:

• Compression: Where the forces push or pull the material to compress it.

• Tension: Where forces pull apart to elongate or stretch the material.

• Shear stress: Which occurs when forces are applied parallel or tangential to a surface.

• Bending: This involves both tensile and compressive stresses when a load is applied across the length of a material.

• Torsion: This is related to twisting forces applied to materials.

Friction, however, is not classified as a type of stress but rather as a resistance force that arises when two surfaces interact. It affects how materials behave under load but is distinct from the types of stress that describe how materials react to applied forces. Understanding these concepts is crucial in fields such as structural engineering and material science, where the performance of materials under various forces is analyzed.