Stress – Restoring force per unit area of strain of cross section acting in scientific material is called Stress.
SI Unit – N/m2 or pascal
Stress is neither a scalar nor a vector stress is a tension of rank 2
Note – Tension having rank 0 is called scalar and having rank 1 is called vector.
The deformation produced in a material body by deforming force is called strain.
(i) Fractional change in length in a material is called longitudinal strain.
= change in length/original length
(ii)Fractional change in volume of a material body due to hydraulic deforming force is called hydraulic strain.
= change in volume/original volume.
(iii) Lateral shift between the adjacent layer of material body separated by unit length is called Tangential strain or shearing strain.
Note. – strain is a ratio so it have neither dimensions nor units