Correct Answer - Option 3 : Intensity of normal stress
Concept:
Normal stress:
It is the intensity of resisting force normal to the sectional plane. it is the ratio of normal force and area.
\({\bf{Normal}}{\rm{ }}{\bf\ {stress}} = \frac{{{\bf{Normal}}{\rm{ }}{\bf\ {force}}}}{{{\bf{area}}}}\)
If the force is compression then it will be compression stress and if the force is tension then the stress will be tension stress.
Strain:
A strain is a ratio between the deformation and the original length. Think of strain as percent elongation, how much bigger or smaller is the object upon loading it.
Ex. A rubber band, when you pull on it, and it gets longer – it stretches. Deformation is a measure of how much an object is stretched.
\({\bf{Strain}} = \frac{{{\bf{Change}}{\rm{ }}{\bf\ {in}}{\rm{ }}{\bf\ {length}}}}{{{\bf{Origional}}{\rm{ }}{\bf\ {length}}}}\)
