Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Equation of Continuity-Three Fire Hoses and Pipes

  1. Jun 7, 2012 #1
    Equation of Continuity--Three Fire Hoses and Pipes

    1. The problem statement, all variables and given/known data

    Three fire hoses are connected to a fire hydrant. Each has a radius of 0.020 m. Water enters the hydrant through an underground pipe of radius 0.080 m. In the pipe the water has a speed of 3.0 m/s. How many kilograms of water are poured onto the fire in one hour? What's the water speed in each hose?

    2. Relevant equations

    A1 x V1 = A2 x V2
    m = V x rho
    I'm not really sure what other equations are relevant.

    3. The attempt at a solution

    I don't even know where to start. I need the volume...I think, and I'm very confused.
  2. jcsd
  3. Jun 8, 2012 #2
    Re: Equation of Continuity--Three Fire Hoses and Pipes

    You know the velocity of the water in the pipe feeding the hydrant. You have the formula for the volumetric flow in a pipe which is Q=A*V. What are the units of the equation? A formula for mass flow is m=rho*Q. And lastly, what enters the hydrant exits the hydrant assuming all the exits are being used. That is what is meant by 'continuity'.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook