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: Hydrostatic equilibrium

  1. Mar 13, 2006 #1

    So, I've been given that archimedes principal for an atmospheric layer of gas on a planet is
    dP/dr = -rho*g
    where g is constant.

    For a vanderwaals gas,
    P = rhot*R*T - a*rho^2

    I used the quadratic formula & solved for rho and put that into the dP/dr equation. getting...

    dP = [((-RT +/- ((RT)^2 - 4aP)^.5) / 2a ] dr

    now i need to separate the variables and integrate, to get P as a function of r, but how do i get P out of the right side of the equation???

  2. jcsd
  3. Mar 13, 2006 #2


    User Avatar
    Homework Helper

    Don't you need an equation for T?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook