1. Collagen fiber is stressed with 12 N force. The cross-sectional area of the fiber is 3 mm2, its coefficient of elasticity is 500 MPa. Give the percentage of relative extension. I think i have found the correct equation but i cant seem to find the rigth answer wich is suposed to be 0.8% but i always end up with 8*10^-4.. 2. Relevant equations F/A=E Δl/l 3. The attempt at a solution 12N/(0,003m^2 * 5*10^6 Pa) and then I get a result of 8*10^-4, and I am stuck.. I belive there is something fundamental I have missed but I can't seem to find it.. Thanks in advance!