Question

define stress and strain with its expression and unit

Answer 1

Stress

Stress is defined as force acting per unit area in the normal direction. The formula for stress is :

$\frac{force}{area}$

The unit for stress is same as that of pressure i.e. Pa (pascal) or N m-2 (Newton per metre squared).

Strain

Strain occurs when force is applied to the object. It is the measure of strech or deformation. It is represented as the ratio of change in length to initial length. Formula for strain is :

$\frac{change \: in \: length}{initial \: length}$

Strain is a dimensionless quantity.