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Problem with Pressure Equation units

  1. Apr 4, 2015 #1
    I was doing a problem that required me to initially find the amount of pressure that was acting on a bubble, I decided that I had to use the equation P=P(STP) + ρgd. But looking at the equation, the units for the ρgd part of the problem doesn't make sense about how that gives me a unit of pressure (Pascal).

    2. So I worked it out and:

    ρ= kg/m^3
    g= m/s^2
    d= m

    when multiplied together your units become kg/ms^2 which you are then adding to a pascal unit. So my question really is, is 1 kg/ms^2 = 1 Pa?

    An explanation would be much appreciated!
  2. jcsd
  3. Apr 4, 2015 #2


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    1 Pascal = 1 Newton / m2

    1 Newton = 1 kg-m/s2 [Using F = m a]

    Therefore, 1 Pascal = 1 N / m2 = 1 kg m/s2 × (1/m2) = 1 kg / m-s2

    Compare with the units arising from the product ρgd. :wink:
  4. Apr 4, 2015 #3
    Thank you so much! Makes sense now!
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