Design engineers in many situations must justify their selection of material. Your role in a mechanical design company that manufactures steel pipes is to confirm the maximum stresses imposed by a 250 psi oil pressure on the pipe wall, which acts as a pressurized cylinder once the gate valve is closed. If the pipe diameter is 1 foot and its wall is 0.25 inches thick. Evaluate the longitudinal and hoop stresses at point A. Valve A oil in Figure.3: Steel oil pipe