1. Not finding help here? Sign up for a free 30min 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!

Simple Static Pressure problem, need help with units

  1. Sep 19, 2011 #1
    1. The problem statement, all variables and given/known data
    Hi i'm having trouble solving this physics problem if anyone can help it would be greatly appreciated !

    Static pressure problem: A bathtub contains water to a depth of 20 inches. Determine the pressure at the bottom of the bathtub in both [psia] and [psig] (a being absolute pressure and g being gauge pressure)


    2. Relevant equations
    im using P=pgh

    3. The attempt at a solution
    what i've tried doing was to find gauge pressure first: P=pgh=(1.94slug/ft^3)(32.2ft/s^2)(1.67ft). I got the 1.67 feet from converting 20 inches to feet. the answer i get is 104.11slug/s^2 but they want it in psi or lb/in^2 and i am having trouble converting these units =[
     
  2. jcsd
  3. Sep 19, 2011 #2
    Why don't you just convert the initial 20 inches to meters then solve for the standard SI units?
     
  4. Sep 19, 2011 #3
    Well the problem is that i don't know how to get rid of the /s^2 in my final answer and even if i use the standard SI units ill still come up with an answer that has /s^2
     
  5. Sep 19, 2011 #4
    That's the acceleration…s^2 is an SI unit.
     
  6. Sep 19, 2011 #5
    Also…

    look at the definition of what a pound actually is (in terms of units). That should fix things.
     
  7. Sep 19, 2011 #6

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Instead of using different unit systems, 1 cu. ft. of fresh water weighs about 62.4 pounds. Knowing that number, you should be able to find psi given the depth of water in the bath tub.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Simple Static Pressure problem, need help with units
Loading...