A fire hose 5 centimeters in diameter is used to fill a 225-liter bucket. If it takes 15 seconds to fill the bucket, what is the speed at ...



Answer :

I believe you ask about speed at the end of the hose:

The volume of the bucket is 225 liters which is equal to 225 [tex]dm^{3}[/tex].
[tex]V=225dm^{3}[/tex]
Hose's cross section can be counted with the typical circle's area formula (with diameter instead of radius, that's why you've got a fraction):
[tex]A=3,14*\frac{d^{2}}{4}}=0,19625dm^{2}[/tex]

[tex]225dm^{3}[/tex] are filled within 15 second.

As the bucket is being filled you can say that it's volume is the volume of the water that flowed out of the hose, then:
[tex]V=A*h[/tex]
The speed of the water can be counted with equation:
[tex]v=\frac{h}{t}[/tex]
After extracting h from the volume's equation you get:
[tex]v=\frac{V}{A*t}[/tex]
When you count the fraction you get the answer:
[tex]v=76,43\frac{dm}{s}=0,7643\frac{m}{s}[/tex]