3. A bar made of A-36 steel has the dimensions shown in Fig. If an axial force of P = 80kN is applied to the bar, determine the change in its length and the change in the dimensions of its cross section after applying the load. The material behaves elastically. Given Est = 200 GPa P = 80 kN 1.5 m 50 mm 100 mm P = 80 kN