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Homework Help: Conceptual problem Dynamics Hibbeler 12 Edition

  1. Nov 1, 2011 #1
    1. The problem statement, all variables and given/known data

    Pl2-4. The pilot tells you the wingspan of her plane and her
    constant airspeed. How would you determine the acceleration
    of the plane at the moment shown? Use numerical values and
    take any necessary measurements from the photo.

    Here is the photo to the problem

    2. Relevant equations

    All data and revelant questions are given on the problem statement

    3. The attempt at a solution

    I try to measure from the photo but didn't know if it was accurate
  2. jcsd
  3. Nov 1, 2011 #2

    Simon Bridge

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    Guiding questions:
    What did you measure from the photo?
    You need to say what you actually did.

    What are the relevant equations?
    None are provided in the problem statement.

    Note: the problem asks for a strategy, not a solution. What was your strategy?
  4. Nov 1, 2011 #3
    I try to measure the span of the smoke created by the plane in order to establish some numerical values and see if that relates to the acceleration but it also talks about the wingspan of the plane, that is part of the confusion I have.
  5. Nov 1, 2011 #4

    Simon Bridge

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    A measurement of so-and-so centimeters on the picture tells you nothing about how far the plane actually went or the dimensions of the motion. If only there was some known length in the picture that you could use as a scale... do you know what kind of acceleration would be important here: you are told the plane flies at a constant speed?
  6. Nov 1, 2011 #5
    Exactly as you there is not much given data and measurements won't help much. Well from the photo it can be say that the plane flies along a circular path but then if that is true, it would have tangential and normal components of acceleration. The planes does flies at constant speed.
  7. Nov 1, 2011 #6


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    It doesn't matter what the plane was doing before it got to its current position, as shown by the smoke trail.

    All that matter is what it is doing when the photo was actually taken.

    Sorry if that is a bit cryptic, but it's hard to give you any hints about this without telling you the answer.
  8. Nov 1, 2011 #7

    Simon Bridge

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    @elvis.2: If the plane flies at a constant speed, what is it's tangential acceleration? (I'm kinda disappointed that you gave up on measurements so quickly - can you think of no way to determine distances in the photo? Are there no known distances in the photo that you can use as a scale?)

    @AlephZero: I'm surprised, surely the type of motion affects the acceleration and the past trajectory is a clue to that motion? Perhaps we need to discuss this behind the scenes - make sure we are on the same page?

    The problem is asking us to guess how the motion continues after the previous curve - which is presumably part of the "conceptual" part.
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