4. Calculate the tensile modulus of elasticity of a unidirectional Kevlar 49-fiber-epoxy composite material that contains 63% by volume of Kevlar 49 fibers. (a) considering is stressed under iso-strain conditions.

(b) considering is stressed under iso-stress conditions.

Data: Kevlar 49 fibers have a tensile modulus of elasticity of 27.5 10^6 psi and the epoxy matrix has a tensile modulus of elasticity of 0.550 10^6 psi.