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Simple Pressure Question

  1. Oct 18, 2009 #1
    1. The problem statement, all variables and given/known data

    I have a balloon full of air, it is at a pressure relative to the ambient pressure of 9.7KPa and its volume is 3000cm3. The balloon is attached to a surface, this seal is airtight and perfect. The surface it is attached to contains a (very) small hole with an area of 0.25mm2. I am struggling to figure out how long it will take for the pressure within the balloon to equal that of the ambient pressure within the room.

    2. Relevant equations

    This is what I am stuck on, I don't have a clue which equation to use.

    3. The attempt at a solution

    I thought that I would start at simplifying almost everything, instead of imagining a balloon attached to a surface I could just imagine a hollow cylinder with a volume of 3000cm2 and the same pressure being synthesised by a force acting on top of the air seeing as though the pressure within the balloon doesn't change until the very last second which I can neglect. I though about imagining it like a syringe with a constant force.
    I calculated that the force of the air after being forced through the hole will be 2.425N. I think that is right, I also figured out that the air would be expelled at 127m/s but this seems a little high, can someone confirm this?

    I would very much like this to be almost totally my own work so if you could just give me a few gentle nudges or a couple a links to a web page I would be eternally grateful.
  2. jcsd
  3. Oct 18, 2009 #2
    Can I use Bernoulli's equation? Or is that fluids only?
  4. Oct 21, 2009 #3
    Never mind, solved it myself
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