Power-grid wires have steel cores (diameter 1 mm) and copper outer layer. Wire total diameter is 2 mm. ECu = 150 GPa, Esteel = 210 GPa. Compute the Youngs modulus of the composite wire? Compute the tensile load that the wire will support before any plastic deformation occurs in it? How long could be the wire before any plastic deformation occurs in it, stressed by its own weight?