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Homework Help: Combined mass acceleration

  1. Jan 18, 2007 #1
    Hi, I am working on a problem that involves the following
    I have a mass of 500 grams travelling at 7m/s that hits and sticks to another mass of 50 grams that was stationary.

    What acceleration does the second ( 50 gram ) mass experience?

    I have tried using a Runge-Kutta 4th order algorithm to solve some Differential Equations of motion and assuming a very high K value for the stiffness of the materials, but I think this is too complex.

    How can I calculate the acceleration, preferably on a time basis, not just assuming that it took 0.1 seconds to get upto the new combined speed of approx 6.9?? m/s.

    Thanks
    Stuman
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  2. jcsd
  3. Jan 18, 2007 #2
    For the information you given.... It is imposssible.
    Period...
     
  4. Jan 18, 2007 #3
    OK. I don't want a numerical answer, I would like a methodology. Basically it is an impact related question where the two masses combine. How do you calculate the acceleration of the second 50 gram mass?
     
  5. Jan 18, 2007 #4

    PhanthomJay

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    Problem is not solvable in the absence of other data.
     
  6. Jan 18, 2007 #5
    What other data would you like?
     
  7. Jan 18, 2007 #6
    If you made a simple assumtion that the accelaration is constant, what you need is the
    time interval of the impact....
     
  8. Jan 18, 2007 #7

    PhanthomJay

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    Or the deformation during impact. Then the whole heap, assuming the impact takes place on a level frictionless surface , would move off at a constant speed of 6.9m/s forever and ever................
     
  9. Jan 18, 2007 #8
    As I said in my original post

    I cannot use constant acceleration of impact time. I need to claculte it on a dynamic basis.
     
  10. Jan 18, 2007 #9

    PhanthomJay

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    Do you think it makes a difference whether the masses are made of soft clay or hardened steel?
     
  11. Jan 18, 2007 #10
    I do think it makes a difference which is why I stated in my original problem that during my RK4 analysis I assumed a high K value for the stiffness of the materials.
     
  12. Jan 18, 2007 #11

    PhanthomJay

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    Why did you assume a high value? why not a low one? If I hadn't posted prior to reading chanvincent's response, i would have let it go at that....It is imposssible.
    Period...
     
  13. Jan 18, 2007 #12
    OK, getting nowhere quick, subject is now closed.
     
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