7. An external force of F is applied to a cube as shown on the figure. Material is isotropic. Determine strain and stress tensor (matrix form, = [01,02, ..., 06]) qualitatively (+, -, 0). (Mind the constrains.) (2 points) 2 1 F - Constrained from expansion or contraction along axis 1 F Free to expand or contract along axes 2 and 3 3. The load-elongation curve represents results of a tensile test of a cylindrical specimen (initial diameter is 4 mm, gauge length is 25 mm). Estimate the Young's modulus. (3 points) Load (kN) 2.5 1.5 0.5 1 2 3 0 0 0.025 0.05 0.075 0.1 0.125 0.15 0.175 0.2 (a) 90 MPa (b) 90 GPa (c) 50 MPa (d) 50 GPa Elongation (mm)