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Homework Help: Intro Physics question

  1. Sep 11, 2011 #1

    I'm not quite sure where to start with this.

    Thank you in advance
  2. jcsd
  3. Sep 11, 2011 #2


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    You must have some idea as to where to start. We can't help you unless you at least attempt the problem first.
  4. Sep 11, 2011 #3
    Well my professor hasn't given any examples yet on this and I can't find any in my textbook either. I was hoping someone could give me pointers on where to start.
  5. Sep 11, 2011 #4


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    You can start by looking on the interweb for things like "measuring the diameter of a molecule". :smile:
  6. Sep 11, 2011 #5
    I haven't done any physics or math in over a year which is probably why I'm having trouble with pretty basic problems.

    Here's my attempt:

    (a) Area of slick = [itex]\pi[/itex]r2
    diameter of slick = 2x1010
    volume of slick= area x thickness
    volume of oil=volume of slick= 1L = 0.001m3


    (b) [itex]\rho[/itex]=M/V
    M=850kg/m3 x 3.14x10-30m3


    does that make sense?
  7. Sep 11, 2011 #6


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    Looks okay, too many significant digits though.

  8. Sep 11, 2011 #7
    Thank you!

    The diamete/thickness was a typo, I wrote it properly on my sheet :)

    As for the significant digits, does 2.5x103m work?
  9. Sep 11, 2011 #8


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    If you are using a number like 2x10-10, I think one SD would suffice.
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