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## Homework Statement

A fire hose has an inner diameter of 5 inches and water is flowing at 600 gal/min. The flow exits through a nozzle contraction with

diameter d

_{n}. For steady flow, what should d

_{n}be in inches in order for the exit velocity to be 25 m/s.

My only question here is really do I even need the given inlet diameter = 5 in ?

As far as I can see. Since density is constant, the volume flow rates at inlet and exit should be equal. That is,

[tex]Q_1=Q_2[/tex]

[tex]\Rightarrow Q_1 = \frac{500\,\text{gal}}{\text{min}} = A_2V_2[/tex]

[tex](\frac{\pi}{4}d_n^2)V_2=\frac{500\,\text{gal}}{\text{min}}[/tex]

Now assuming I convert my units properly, this should be correct? It's just that given inlet diameter that's bugging me.

Thanks.