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: Actual tyre pressure

  1. Jun 22, 2011 #1
    1. The problem statement, all variables and given/known data

    On a warm day, a student uses a tire gauge to test the air pressure of her tires. While listening to the weather report on the way to the garage, she finds that the barometric pressure is 780mmHg. If the gauge reads a pressure of 35psi, what is the actual pressure inside the tires in psi?

    2. Relevant equations

    I don't know which equation I should be using. Is it a trick question because the tyre pressure doesn't change or is it
    Pgauage= Pabsolute - Pambient

    3. The attempt at a solution

    if it is then I'm assuming that absolute pressure is the same as actual pressure.
    Pgauage= 35psi
    Pambient= 780mmHg= 15.0868psi
    and I have to find Pa
    which would be
    Pabsolute=35 + 15.0868
    = 50.868 psi

    Like I said I have no idea....thanks!
  2. jcsd
  3. Jun 22, 2011 #2


    User Avatar
    Homework Helper

    It looks all right, but the end result. Check the addition! :smile:

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook