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Question 1: a) A copper tube having an external diameter of 40mm and an internal diameter of 29mm has a steel rod of 20mm diameter inside of it. The two materials are rigidly joined at their ends. If a compressive load of 68 kN is applied to the bar, determine (i) the stresses in each material due to the applied load. [10 marks] (ii) the extension of the bar [2 marks] For steel; E= 190 GN/m² For copper; E = 100 GN/m² Length of bar = 2.3m Question 2: i. If a material has E = 312 GPa and another with E= 145 GPa, which of the two is more stiff? [1 mark] ii. SAE uses a four-digit designation code for carbon and alloy steels. Explain [2 marks]