An $18-$in diameter, $2-$mile long commercial steel pipeline discharges freely at its lower end under a head of $200$ ft$.$ The wall thickness of the pipe is $0\mathrm{.}2$ in and Ep $=4\mathrm{.}32\backslash$times $109$lbf$/$ft$2$ for commercial steel. Assuming that the pipe compressibility characteristics are negligible related to the compressibility of the water, compute the stress that would develop in the walls of the pipe if a valve is installed in the pipe near the downstream end. Be sure to include the pressure in the pipeline and any pressure induced by water hammer. Also compute the minimum safe time of valve closure to prevent a water hammer wave in the pipeline.