Aluminum 6061-T6 has a density of 2.7 g/cm^3, a Young's modulus of 69 GPa, and an ultimate tensile strength of 310 MPa.
If a "spring" were to be made by pulling a 10cm long cylinder of material in tension with a desired stiffness of 5000kN/m, what should the diameter (in millimeters) be for an Aluminum "spring"?
I dont want the answer for this question but the FORMULA for working it out as i am totally unsure how to derive the diameter from the info given..