If stress is given by equation 1 which implies that stress

[jahlin]

Homework Statement

If stress is given by equation 1 which implies that stress is independent of material and the 2nd equation implies it depends on the material. Inst it a contradiction?

Homework Equations

Normal stress is given by $$\sigma$$=f/A (1)
and $$\sigma$$=E$$\epsilon$$ (2)

The Attempt at a Solution

 

[Mapes]

Appearance (or lack of appearance) in the same equation doesn't imply dependence. The equation $2=xy$, for example, doesn't imply that the value 2 depends on the value of $x$.

If strain (stress) is a known function, the associated stress (strain) is material dependent.