The document derives expressions for Young's modulus in terms of other elastic constants like modulus of rigidity and bulk modulus. It considers a solid cube subjected to shear forces, which causes diagonal strains. Using relationships between shear strain, normal stress, longitudinal strain, and lateral strain, it arrives at the expression E = 2G(1+μ), where E is Young's modulus, G is modulus of rigidity, and μ is Poisson's ratio. It then considers a cube under mutually perpendicular tensile stresses and derives another expression for E in terms of bulk modulus.