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!

Tank pressure

  1. Oct 2, 2015 #1
    1. The problem statement, all variables and given/known data

    What is the headspace pressure (air)?

    Closed tank part filled with fluid under pressure, there are tubes that indicate the fluid level and pressure. The tube on the left is open to atmosphere.

    fluid s.g. 1.2
    x = 5m
    y= 1.7m


    2. Relevant equations

    See below

    3. The attempt at a solution

    Assuming atmospheric pressure and rho*g*h come into play?
  2. jcsd
  3. Oct 2, 2015 #2
    Last edited: Oct 2, 2015
  4. Oct 2, 2015 #3
    Why? I was wondering whether to use boyles law as the tank full of air at atmospheric will have been compressed as the tank filled?
  5. Oct 2, 2015 #4
    never mind
  6. Oct 2, 2015 #5
  7. Oct 2, 2015 #6
  8. Oct 2, 2015 #7
    Can you please provide an exact statement of the problem.
  9. Oct 2, 2015 #8
    Hi the exact statement contains no further info except a couple of filler words such as the, and etc.

    Though it doesn't state about it being heads pace or air pressure it's just the area above the fluid.
  10. Oct 2, 2015 #9
    If atmospheric pressure is present at the top of the left column of water, what is the pressure in the left column of water at the level of the dashed line in the tank?

  11. Oct 3, 2015 #10
  12. Oct 3, 2015 #11


    User Avatar
    Science Advisor

    The pressure at the top of the column is atmospheric...The pressure lower in the column is found via Pascals law
  13. Oct 5, 2015 #12
    Last edited: Oct 5, 2015
  14. Oct 5, 2015 #13
    Let's check. If that's the pressure at the level of the dotted line, what is the pressure at the bottom of the tank? And also, based on your result, what is the pressure at the top of the left column of fluid?

    If you are not able to solve this problem, you need to go back to your textbook and re-read the sections on hydrostatic pressure. If you encounter difficulties with understanding those sections of the textbook, we are prepared to help answer specific questions you may have.

  15. Oct 5, 2015 #14
    I fail to see how I can elaborate further with the info give. I have numerous textbooks, the unconventional setup is throwing me somewhat.
  16. Oct 5, 2015 #15


    User Avatar
    Science Advisor

    Can you state in your own words what the 'h' in the equation in your OP represents?
    If not, can you find a definition in one of your textbook?
  17. Oct 5, 2015 #16
    Head of liquid (the x and y values)
  18. Oct 5, 2015 #17


    User Avatar
    Science Advisor

    'h' is the height of fluid above the point of measurement.

    So what is the height of fluid above the point you are interested in (the dotted line)?
  19. Oct 5, 2015 #18
    Interested in the area above the dotted line, 5metres
  20. Oct 5, 2015 #19


    User Avatar
    Science Advisor

    So what now? Can you reach the answer?
  21. Oct 5, 2015 #20
    No that is where I am stuck, I can calculate the fluid pressure but the air pressure I am lost.

    1200kg.m^-3 * 5m * 9.81m.s^-2 = 58680N.m^-2
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted