3. In designing structures and machines, it is important to consider strength of material so that the material should have an adequate strength to resist applied loads or forces and retain its original shape. Strength of a material is its ability to withstand this applied load without failure or plastic deformation. The bar shown below is subjected to a tensile load of 160 kN. If the stress in the middle portion is limited to 150 N/mm, determine the diameter of the middle portion. Find also the length of the middle portion, if the total elongation of the bar is to be 0.2 mm. Take the young's modulus = 2.1 x105 N/mm 160 kN 6 cm DIA 40 cm 160 kN 6 cm DIA (Bansal, 2006)