This question is similar to a question I am stuck on, but I have changed it to get an understanding how to works.
A spring is being made by pulling a 12cm long cylinder of material in tension with a desired stiffness of 6200kN/m.
It has a density of 2.9 g/cm^3, an ultimate tensile strength of 375 MPa and a Young's modulus of 70 GPa.
What should the diameter (in mm) be for the metal "spring"?
So, my question is how can I go about solving this question?
I have looked at the Young's Modulus and Hooke Law's formulas. But keep getting stuck with material displacement. Do I need to know the amount of length the object changes to work out this solution, or am I on the wrong track?
Can I assume: $\Delta L = 1$ if I used the following formula to find the $A_0$, which I can then calculate the diameter from: $$ F = \frac{E A_0 \Delta L}{L_0} $$
Any help will be most appreciated.