If we have multiple loads on an axial bar as shown with the following parameters, what is the elongation of the middle section (the section between the applied loads of F1 and F2) in microns? k1=224 kN/mm k2=158 kN/mm k3-117 kN/mm F1=1 kN F2=1.0 kN F3=4 kN Type your answer... Fi F k3 >F3 L3