Q.10. The nodal displacements of rectangular element having nodal coordinates (0, 0), (4, 0), (4, 2) and (0,2) are: -u=0 mm, V-0 mm, u2=0.1 mm, V2=0.05, U3-0.05mm, V3--0.05mm, U4=0 mm and V4= 0 m respectively. Determine the stress matrix at r=0 and s=0 using iso parametric formulation. Take E=210GPa and poission's ratio=0.25. f