A one mm diameter steel wire is wound around a copper tube with external and internal diameters of 140 mm and 120 mm respectively, to increase the strength of the tube against internal pressure. Find, what initial tension must be given to the wire, so that maximum allowable stresses for the tube and wire materials namely 90 and 200 MPa respectively are reached simultaneously. Assume m for copper and steel to be 0.3 and wire winding as a thin cylinder. Modulus of elasticity for copper and steel may be assumed as 106 and 2×106 MPa respectively. The tube is open at the ends.