Consider a column of concrete that is under a compressive load. The column can be considered a cylinder, as illustrated in the figure below. The cylinder has an initial length lo, and cross-sectional area A. When it is under load the length reduces to 1. The concrete has a Young's modulus of E= 20.0 GPa and shear modulus of G = 8.7 GPa. The initial cross-sectional area is A, = 0.785 m. Under load, the radius increases by 0.4 mm, and the final length of the column is /= 1.5 m. Assuming that the deformation is elastic, and that the concrete is an isotropic solid, what is the initial length (7) of the cylinder before the load is applied? Express your answer in units of meters and show your work. Ao 10 F F