An element in plane stress is subjected to stresses (x = - 8400 psi, (y = 1100

Question:

An element in plane stress is subjected to stresses (x = - 8400 psi,
(y = 1100 psi, and Txy= - 1700 psi (see figure). The material is aluminum with modulus
of elasticity E = 10,000 ksi and Poisson's ratio v = 0.33.
Determine the following quantities: (a) the strains for an element oriented at an angle ( = 30o, (b) the principal strains, and (c) the maximum shear strains. Show the results on sketches of properly oriented elements.