As shown in Fig. P8.82, a standard household water meter is incorporated into a lawn irrigation system

Question:

As shown in Fig. P8.82, a standard household water meter is incorporated into a lawn irrigation system to measure the volume of water applied to the lawn. Note that these meters measure volume, not volume flowrate. With an upstream pressure of \(p_{1}=50 \mathrm{psi}\) the meter registered that \(120 \mathrm{ft}^{3}\) of water was delivered to the lawn during an "on" cycle. Estimate the upstream pressure, \(p_{1}\), needed if it is desired to have \(150 \mathrm{ft}^{3}\) delivered during an "on" cycle. List any assumptions needed to arrive at your answer.

Figure P8.82