7. (a) Sketch a typical engineering stress-strain graph (b) How do you obtain Elastic/Young's modulus from the graph? c) How do you calculate yield strength from the graph? (d) How do you obtain tensile strength from the graph? (e) Where does the plastic deformation start? (bonus) Sketch true-stress vs true-strain on the same graph. What is the main difference between engineering and true stress strain diagram and where do they separate