# Water flows through a fire hose of diameter 6.40 cm at a speed of 5.9 m/s. Find the flow rate of the fire hose in L/min?

## (The Answer is 1,140 L/min) i need help solving it.)

May 2, 2017

I got the same $1140 \frac{L}{\min}$

#### Explanation:

I would use the fact that the flow rate $R$ is related to the cross cectional area and velocity as:
$R = A v$
considering a velocity $v = 5.9 \frac{m}{s} = 590 \frac{c m}{s}$
and a cross sectional area of:
$A = \pi \cdot {\left(\frac{d}{2}\right)}^{2} = \pi {\left(\frac{6.40}{2}\right)}^{2} = 32.17 c {m}^{2}$
we get:
$R = 590 \cdot 32.17 = 18980.3 \frac{c {m}^{3}}{s}$
we need to convert it ito $\frac{L}{\min}$
We know that:
$1 L = 1000 c {m}^{3}$
and
$1 \min = 60 \sec$
so we get:
$R = \frac{\frac{18980.3}{10000}}{\frac{1}{60}} = 1138.8 \approx 1140 \frac{L}{\min}$