A plate in equilibrium is subjected to uniform stresses along its edges with magnitude 𝜎𝑥𝑥 = 30 MPa

Q. A plate in equilibrium is subjected to uniform stresses along its edges with magnitude 𝜎_𝑥𝑥 = 30 MPa and 𝜎_𝑦𝑦 = 50 MPa as shown in the figure

The Young’s modulus of the material is 2×10¹¹ N/m² and the Poisson’s ratio is 0.3. If 𝜎_𝑧𝑧 is negligibly small and assumed to be zero, then the strain 𝜀_𝑧𝑧 is

(A) -120×10^-6           (B) – 60×10^-6           (C) 0.0                          (D) 120 ×10^-6

Ans: -120 × 10^-6