Explain what is stress? Write its unit and dimensional formula.

(N/A) When forces are applied on a body such that it remains in static equilibrium,it undergoes deformation.
The extent of deformation depends on the nature of the material and the magnitude of the deforming force.
When a body is subjected to a deforming force,a restoring force is developed within the body to oppose the deformation.
This restoring force is equal in magnitude but opposite in direction to the applied force. The restoring force per unit area is defined as stress.
If $F$ is the applied force and $A$ is the cross-sectional area of the body,then:
$\text{Stress} = \frac{F}{A}$
The $SI$ unit of stress is $N m^{-2}$ or Pascal $(Pa)$.
The dimensional formula of stress is $[ML^{-1} T^{-2}]$.