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: Gauge pressure at the bottom of a barrel

  1. May 4, 2016 #1
    1. The problem statement, all variables and given/known data
    A barrel contains a 0.110 m layer of oil and a density of 690 kg/m3 floating on water that is 0.300 m deep. What is the pressure at the bottom of the barrel?

    2. Relevant equations

    3. The attempt at a solution

    Poil + Pwater = Ptotal

    My question is why am I using this formula? I got the correct answer, but initially I wanted to treat the pressure of the water as a negation of the pressure of the oil, causing the barrel to float. So, Poil - Pwater. Is the reason for the addition because I am treating the bottom of the barrel as a point and the pressure acting on it in every direction equally and taking my gauge pressure from that exact point?

  2. jcsd
  3. May 4, 2016 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    My reading of the question is that both the oil and the water are in the barrel.
  4. May 4, 2016 #3
    Okay, thank you. I mis-read that. I was assuming the barrel was floating on the water. Paying attention to sentence structure is useful. ?:)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted