$4\mathrm{.}5\mathrm{.}3$ The pressure difference between points $1$ and $2$ in the series

pipe system in Figure P$4\mathrm{.}5\mathrm{.}3$ is $15$ psi $.$ All the pipes are galvanized

iron with roughness value of $0\mathrm{.}0005$ ft $.$ The loss coefficient at the

sudden contraction is $0\mathrm{.}05.$ Determine the flow rate in the system.

The prevailing temperature is $70F.$

Figure P$4\mathrm{.}5\mathrm{.}3$