A copper rod of cross-sectional area 0.500 cm2 and length 1.00 m is elongated by 2.00 * 10-2 mm, and a steel rod of the same crosssectional area but 0.100 m in length is elongated by 2.00 * 10-3 mm . (a) Which rod has greater tensile strain? (i) The copper rod; (ii) the steel rod; (iii) the strain is the same for both. (b) Which rod is under greater tensile stress? (i) The copper rod; (ii) the steel rod; (iii) the stress is the same for both.

A 25-mm-diameter aluminum rod, 4 m long, is subjected to an axial tensile load of 50 kN Assume a proportional limit of 200 MPa and E = 70 GPa. Compute: a) Stress b) Strain c) Total elongation

Narrow bars of aluminum are bonded to the two sides of a thick steel plate as shown. Initially, at T₁ = 70°F, all stresses are zero. Knowing that the temperature will be slowly raised to T₂ and then reduced to T₁, determine (a) the highest temperature T₂ that does not result in residual stresses, (b) the temperature T₂ that will result in a residual stress in the aluminum equal to 58 ksi. Assume aa = 12.8 x 10-6/°F for the aluminum and a = 6.5 × 10-6/°F for the steel. Further assume that the aluminum is elastoplastic with E = 10.9 × 106 psi and ay = 58 ksi. (Hint: Neglect the small stresses in the plate.) Fig. P2.121