Tutorial Question on Axially Loaded Members Question One A steel bar 2.4 m long has a circular cross section of diameter d₁ = 20 mm over one-half of its length and diameter d2 =12 mm over the other half (see figure part a). The modulus of elasticity is E = 205 GPa. (a) How much will the bar elongate under a tensile load P = 22 kN? (b) If the same volume of material is made into a bar of constant diameter d and length 2.4 m, what will be the elongation under the same load P? |d₁ = 20 mm d₂ = 12 mm P P=22 kN 1.2 m 1.2 m (a) Question Two A two-story building has steel columns AB in the first floor and BC in the second floor, as shown in the figure. The roof load Pi equals 400 kN and the second-floor load P2 equals 720 kN. Each column has length L-3.75 m. The cross-sectional areas of the first- and second-floor columns are 11,000 mm² and 3900 mm², respectively. (a) Assuming that E=206 GPa, determine the total shortening Sac of the two columns due to the combined action of the loads P1 and P2. (b) How much additional load Po can be placed at the top of the column (point C) if the total shortening Sac is not to exceed 4.0 mm?