Elasticity-young’s modulus-modulus of rigidity

Question

Question 1: Define the terms: Elasticity, elastic limit, Young’s modulus and modulus of rigidity.

Question 2: Derive the relation between E, G and K.

Question 3: Draw the stress-strain relation for mild steel. Describe its salient points.

Question 4: The extension of a rectangular steel bar of length 800 mm and of thickness 20 mm is found to be 0.21mm. The bar tapers uniformly in width from 80 mm to 40 mm. If the E for the bar is 2 x 10⁵ MPa, determine the axial tensile load on the bar.

Question 5: A steel tube 24 mm external diameter and 18 mm internal diameter encloses a copper rod 15 mm diameter to which it is rigidly connected t the two ends. If a temperature of 10⁰C there is no longitudinal stress, compute the stresses in the rod and the tube when the temperature is raised to 200⁰C.

Take E_S = 210GPa, E_C= 100GPa, α_S= 11x10^-6 per⁰C and α_C= 18x10^-6 per⁰C.