1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Bernoulli's Equation and stream of water

  1. Aug 7, 2009 #1
    1. The problem statement, all variables and given/known data

    The figure below shows a stream of water in a steady flow from a kitchen faucet. At the faucet the diameter of the stream is 1.20 cm. The stream fills a 125 cm3 container in 18.2 s. Find the diameter of the stream 13.0 cm below the opening of the faucet. (The answer should be in cm)

    2. Relevant equations
    A1v1=A2v2 and P1+0.5densityv^2+density(gh)=P2+0.5(density)v^2+density(gh)

    3. The attempt at a solution
    Not sure how to attempt this problem. I found the speed at which the water flows
    I used the rate (125cm3/18.2)/(0.6^2)pi=6.078 cm/s, but not sure if this information is relevant or not
  2. jcsd
  3. Aug 7, 2009 #2

    Chi Meson

    User Avatar
    Science Advisor
    Homework Helper

    This can be done without the Bernoulli equation. Assuming the stream does not break up, the volume flow rate should remain constant. The speed will increase according to simple conservation of energy (potential to kinetic). Actually, that's all Bernoulli's eq is, conservation of energy-per-unit-volume.

    After finding the final speed, find the necessary diameter of the stream to provide the same volume flow rate you started with.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook