Use FEM to determine the axial force \(P\) in each portion, \(A B\) and \(B C\), of the uniaxial bar shown in figure 1.7. What are the support reactions at \(A\) and \(C\) ? Young's modulus is \(E=\) \(100 \mathrm{GPa}\); the areas of the cross sections of the two portions \(A B\) and \(B C\) are, respectively, \(1 \times 10^{-4} \mathrm{~m}^{2}\) and \(2 \times 10^{-4} \mathrm{~m}^{2}\) and \(F=10,000 \mathrm{~N}\). The force \(F\) is applied at the cross section at \(B\).