Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Psi -> pounds lifted?

  1. May 21, 2010 #1
    psi --> pounds lifted?

    I have a very, very small air compressor that puts out 0.8 bar or 11.6 PSI. I would like to know how to compute if I were to put a plastic skin over the top of the output (like a balloon), how much weight could be lifted by the air compressor.

    I realize that part of the equation is going to be the stretchiness of the skin. Here’s the skin I'm using right now: https://www.amazon.com/gp/product/B000RFU0PS/ref=oss_product (Of course, I’d prefer to understand how the skin factors into the equation so that I can learn and do this myself.)

    For a simple visual, think laying a book on top of an inflating balloon. How much can the book weight before the compressor maxs out?

    Thank you in advance for some guidance.
     
  2. jcsd
  3. May 21, 2010 #2
    Re: psi --> pounds lifted?

    Pressure is a force per unit area. Assuming the force is uniform across the nozzle, then the total upward force should be P x N, where N is the nozzle cross-sectional area.

    In order to lift something, this force must overcome gravity, ie PN > mg, where m is the mass of the object to be lifted and g the acceleration of gravity.

    The condition PN/g > m places an upper limit on the mass you can lift.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook