Define stress and explain types of stress?

Hint:Keep in mind that stress always depends on strain that means, stress is a cause of strain, and if a body does not develop deformation on strain it will not produce stress.

Complete step by step solution:
“Force applied per unit area in a deformed solid is called stress” the SI unit of stress is \[N/{{m}^{2}}\] if you apply some force to produce deformation in a rectangular bar the force applied to change the shape or cause deformation in that rectangular bar is called stress. The formula of stress
\[=\dfrac{F}{A}\]
 Where,
\[\begin{align}
  & F=Force \\
 & A=Area \\
\end{align}\]

Force has 3 types:
Tensile stress
Volumetric stress
Shear stress

TENSILE STRESS:
When there is a 1 dimensional, linear, longitudinal deformation or a body is under tension or compression, even if a normal force is applied to the body the change or deformation caused on it by the force will be termed as tensile stress.

VOLUMETRIC STRESS:
When the deformation in a body is 3 dimensional and it is bringing some change in the volume of an object it will be termed as volumetric stress.

SHEAR STRESS:
When the deformation in a body is angular which means, when we apply Tangential force on a body to change its shape or to twist it, it will be termed as Shear stress.

NOTE: As given above, we understand that any force that changes the volume, angle or compresses of an object will be termed as stress. And here we are talking about the physical stress on anybody.