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: Fluid pressure physics homework

  1. Sep 14, 2008 #1
    A 0.800 m-diameter vat of liquid is 2.70 m deep. The pressure at the bottom of the vat is 1.20 atm.

    What is the mass of the liquid in the vat?
  2. jcsd
  3. Sep 15, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi jason_r! Welcome to PF! :smile:

    Show us what you've tried, and where you're stuck, and then we'll know how to help. :smile:

    Hint: find the density first.
  4. Sep 16, 2008 #3
    Re: Welcome to PF!

    so far i have :

    PA=P_oA +mg
    (1215600)(pi*(0.4)^2)= (1.013x10^5)(pi(0.4)^2) + 9.8m
    m=1.04 x 10^4kg

    I need confirmation on the answer and if im doing this right
    cause i dont have a key or anything
  5. Sep 17, 2008 #4


    User Avatar
    Science Advisor
    Homework Helper

    Yes, that's fine:

    (I haven't checked your value for 1 atm … and I'm assuming you meant 10^6, so that it matches the 1215600)

    You've used a force equation … force on the bottom minus force on the top = weight … P-A - P+A = mg.

    You could also have use the pressure equation (that's the one I'd have used): P- - P+ = rho gh.

    But they both give the same result, and they're both fine. :smile:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook