Stress is measured by the deforming force per unit normal area.

Stresses set up in an object due to of the action of forces can be divided into three broad categories

(a) Tensile stress, which gives elongation, is the answer of forces operating on the body along a one direction.

(b) Shear stress, which gives "shear or bending" being the result of similar and opposite torque about the origin of mass operating on a body.

(c) Volume stress (Bulk Stress) which makes a change in the volume of the body - the resulting strain is called as volume strain (Bulk Strain).