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Intro Physics question

  1. Sep 11, 2011 #1
    physics2.jpg

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

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

    Hootenanny

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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

    lewando

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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

    0.001m3=([itex]\pi[/itex]r2
    r=1261.57m
    d=2523m


    (b) [itex]\rho[/itex]=M/V
    V=[itex]\pi[/itex]r3
    =[itex]\pi[/itex](1x10-10)3
    V=3.14x10-30m3
    M=850kg/m3 x 3.14x10-30m3

    M=2.67x10-27kg

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

    lewando

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    Looks okay, too many significant digits though.

    V=[itex](4/3)\pi[/itex]r3
     
  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

    lewando

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