Define Young's modulus, Bulk modulus and Shear modulus.

Explanation

1. Young.s Modulus Y : Within elastic limit,
the ratio of longitudinal stress to longitu-
dinal strain is called Young.s modulus
i.e., `Y=("Longitudinal stress")/("Longitudinal strain")`
`=(F//A)/(Delta//L)=(FL)/(ADeltaL)`
2. Bulk Modulus `(B)` : Within elastin limit,
the ratio of volumetric stress to volumetric
strain is called Bulk modulus
i.e.,`B=("Volumetric stress")/("Volumetric strain")`
`B=(F//A)/(DeltaV//V)=(FV)/(A.DeltaV)`
Shear modulus or Rigidity Modulus `(G)` :
Wihtin elastic limit, the ratio of tangential
or shearing stress to shearing strain is cal-
led Shear modulus or Rigidity modulus.
i.e.,`G=("Shearing stress")/("Shearing strain")=(F//A)/(theta)=(F)/(Atheta)`