Beer & Johnston — Stress and Strain—Axial Loading: Problem 2.4

2.4 A cast-iron tube is used to support a compressive load. Knowing that \( E = 69 \text{ GPa} \) and that the maximum allowable change in length is \( 0.025\% \), determine (a) the maximum normal stress in the tube, (b) the minimum wall thickness for a load of \( 7.2 \text{ kN} \) if the outside diameter of the tube is \( 50 \text{ mm} \).