The following data refers to an extension spring made from AISI 1085 music wire: mean coil diameter = 15 mm; wire diameter = 1.8 mm; number of active coils = 53. The spring is made with full round...

Extracted text: The following data refers to an extension spring made from AISI 1085 music wire: mean coil diameter = 15 mm; wire diameter = 1.8 mm; number of active coils = 53. The spring is made with full round hooks and is wound with an initial tension which induces a stress of 115 MPa in the wire. Calculate: a) The spring rate, k. b) The ultimate tensile strength and the torsional stress at yield. c) The initial tension and the force required to overcome it.