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Homework Help: Laws of Fluids

  1. Aug 21, 2011 #1
    Question : A balloon tied to a thread whose other end is fixed to the bottom of a beaker is held such that the string is horizontal. The path traced by the balloon if it is released is ?
    Answer : The path is along the arc of a circle

    Please explain why the path will be along the arc of a circle..

    Helppp!
     
  2. jcsd
  3. Aug 21, 2011 #2

    Doc Al

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    What forces act on the balloon? Compare this to the following: What if you had a rock tied to a string and it was released from a horizontal position. What path would it take?
     
  4. Aug 21, 2011 #3
    Well, the forces acting on the balloon are : the tension in horizontal direction, buoyant force and its weight.
    And the rock would take tangential path wouldn't it?
    But how will it go along the arc of a circle?
     
    Last edited: Aug 21, 2011
  5. Aug 21, 2011 #4

    Doc Al

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    OK. Note that the direction of the string tension will change as the string changes position.
    Tangential to what?
     
  6. Aug 21, 2011 #5
    No wait, the rock was released from a HORIZONTAL position, so it would just take a linear path :/
     
  7. Aug 21, 2011 #6

    Doc Al

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    If there were no string attached, the rock would just fall straight down. What does the string do?
     
  8. Aug 21, 2011 #7
    Well the string exerts a pulling force on it..

    But how does this relate to the direction Sir?
     
  9. Aug 21, 2011 #8

    Doc Al

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    Right.
    Don't you think that having a string pulling sideways would affect the direction of motion?
     
  10. Aug 21, 2011 #9
    Yes! But how exactly would it affect the direction?
     
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