For each of the following problem, check the applicability of the thin-wall theory. Unless...

For each of the following problem, check the applicability of the thin-wall theory. Unless otherwise noted, the stated diameter represents an inside diameter.

A welded water pipe has a diameter of 9 ft and a wall of steel plate . thick. After fabrication, this pipe was tested under an internal pressure of 225 psi. Calculate the circumferential stress developed in the walls of the pipe.