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!

High altitude balloon gas expansion

  1. Jun 28, 2009 #1
    1. The problem statement, all variables and given/known data

    Could someone help me calculate the rate of expansion of gas (helium or hydrogen) in a balloon at differant altitudes.

    temperature is -30f at all altitudes

    http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html <- chart for air pressure

    2. Relevant equations

    What would the diameter of a balloon filled with helium OR hydrogen be at 30k 60k and 90k feet have to lift 500lbs total.

    3. The attempt at a solution

    around 23 ft at sea level
     
  2. jcsd
  3. Jun 28, 2009 #2

    ideasrule

    User Avatar
    Homework Helper

    I'm having trouble understanding. Is the balloon rising up at a constant speed? Is it just let go and free to rise? If you suddenly change a balloon's altitude, it would expand or contract because the atmospheric pressure is now different, but the expansion would stop once an equilibrium is reached.
     
  4. Jun 28, 2009 #3
    Take the pressures from 30k, 60k and 90k, and find out how big the balloon would have to be to lift a total wieght of 500 lbs at these altitudes.
     
  5. Jun 28, 2009 #4

    LowlyPion

    User Avatar
    Homework Helper

    Well you know the buoyancy required is 500 lbs. You will want to know at each of those pressures how big a volume is needed to supply the difference in weight of the air displaced and helium or hydrogen (choose one) at the same pressure.

    Careful of your units.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: High altitude balloon gas expansion
  1. Expansion of a gas (Replies: 12)

Loading...