The normal stress xx of 100 MPa and shear stress T xy of 25 MPa are applied on a unidirectional angle-ply lamina containing fibers

The normal stress σ xx of 100 MPa and shear stress T xy of 25 MPa are applied on a unidirectional angle-ply lamina containing fibers at an angle θ as shown in the figure. Determine the stresses in the principal material directions for θ = 0 degree, 15 degree, 30 degree, 45 degree, 60 degree, 75 degree, and 90 degree. Do these stresses remain the same (a) if the direction for the shear stress T xy is reversed and (b) if the fiber orientation angles are reversed?