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Physics question

  1. Jun 27, 2006 #1


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    The Titanic is cruising at 25 knots in a no-wind condition. A typical woman in her 50's duplicates the scene from the movie where she stretches out her arms at the front of the boat.

    Due to the extreme aerodynamic drag from the woman's flapping arms, how long will it take to slow the Titanic to 5 knots?
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  3. Jun 27, 2006 #2
    I think the vessel will come to an abrupt stop at the bottom of the sea bed, way before the woman can slow it down to 5 knots ( even if she started from Belfast :D )
  4. Jun 27, 2006 #3


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    Are you kidding? Extreme aerodynamic drag?

    At the worst case, with an average standing person relating to a [tex]C_D A = 9 ft^2[/tex], that results in a Drag force of about 19 Lbf at 25 kts.

    The titanic was 46,328 tons. Doing a cheesy F=ma and assuming that drag and acceleration were constant (which they wouldn't be) that works out to a distance of approximately [tex]4.11 x 10^7 m = 2.56 x 10^4 miles[/tex]
    Last edited: Jun 27, 2006
  5. Jun 27, 2006 #4

    Chi Meson

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    Obviously not enough information:

    what did the woman eat for dinner?

    Was it a floral print dress? Woven or knit? Cotton, silk, wool, etc?

    Earings: diamond studs, gold hoops? What?

    That's the thing I hate most about these elementary problems; they fail to take real world singificance into account!
  6. Jun 27, 2006 #5


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    I'm pleased to see Fred step up to the plate and take this problem seriously, as any engineer should. :rofl:

    With or without full speed ahead? :rofl:

    Typical woman of what era?
  7. Jun 27, 2006 #6


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    Couple seconds, tops!

    But the more interesting question is will the extreme deceleration spill the woman into the soup?
  8. Jun 27, 2006 #7


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    I bet she is wearing ultra high traction deck loafers and support hose with high elastic modulus in the longitudinal direction. :biggrin:
  9. Jun 27, 2006 #8


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    Sorry, here's a link to a pic, the one with the cup holder and the cool hat. Is this what the members of the sisterhood will look like in 30 years?


    To help recover from that pic of a couple of typical older women, a cute pic of our doggy:

    Last edited: Jun 27, 2006
  10. Jun 27, 2006 #9
    :rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :cry: :rofl: :rofl:
  11. Jun 28, 2006 #10
    Any drag effects could be countered by positioning her atop the funnel arms akimbo again, and letting here act as a human sail, with a good tail wind maybe the Titanic could of avoided disaster by seconds. Why did no one think of this? It's shocking! The unsinkable ship could of winked at God, and our Empire would have remained obscenely proud of her, till we cut her up and used her for tanks during the second world war at least, see! No ones thinking of the damage such a sinking did to our economy, all anybodies thinking about is the drag effect of the crone. Tragiclly shortsighted!

    This is a minimum information puzzle btw no ones mentioned if she was smoking a pipe, how on Earth are we suposed to work anything out from that!:rolleyes::wink:
  12. Jun 28, 2006 #11
    This is a really a psych question.

    5 minutes for the ship's drag coefficient to slow it down...

    -because the ships Captain ordered "All Stop", so he can rush down
    to save the apparently suicidal lady.
    Last edited: Jun 28, 2006
  13. Jun 28, 2006 #12


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    The answer is 4
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