(Solved): Please answer correctly The flat-bar plastic test specimen using for tensile testing is shown in th ...

The flat-bar plastic test specimen using for tensile testing is shown in the figure. The dimension of its cross-sectional area is $3\mathrm{mm}\times 6\mathrm{mm}$. During a testing using a load of $P=5500\mathrm{N}$, the strains measured using optical tracking system along the axial and lateral directions are $0.255(\mathrm{mm}/\mathrm{mm})$ and $?0.092(\mathrm{mm}/\mathrm{mm})$, respectively. The plastic material is assumed to be homogeneous, isotropic and behaves linearly and elastically. (1) Determine the magnitude of stresses along the three directions, and determine the modulus of elasticity and Poisson's ratio of the plastic material. (15\% in total, $5\%$ for each answer) (2) Determine the dilatation of the plastic material. (15\%)