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Impact force from a falling object

  1. Nov 11, 2011 #1
    I used some formulas to determine the impact force of a bubble wrapped 1kg object dropped 1 meter and traveling .03m after impact. But I need some help with the next part. What if an identical bubble wrapped 1kg object is placed on top and both are dropped at the same time? Will the wrapping between the two objects cause the top object to feel the same impact force? Will the bottom object feel more impact force or does the wrapping between them eliminate any influence from the top object? Thanks!
     
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  3. Nov 11, 2011 #2

    sophiecentaur

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    Hi
    Which formulas?
     
  4. Nov 11, 2011 #3
    Sophie,
    I appreciate the quick response. I used these formulas: velocity(m/s) = √2gh, kinetic energy(joules) = 1/2(mv²), impact force(Newtons) = joules/distance traveled after impact, equivalent G-force = Newtons/(kg*gravity). I also cheated and used the calculator at this Georgia State U website: http://hyperphysics.phy-astr.gsu.edu/hbase/flobi.html

    Thanks
     
  5. Nov 11, 2011 #4

    sophiecentaur

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    I think you have chosen a very difficult problem to solve here. You may be better to consider the case of two masses connected by springs, with a second spring between the first mass and the wall. Then the second mass would only be experiencing forces from the first mass during the impact. That would boil down to a fairly straightforward 'waves on a short transmission line' problem.
     
  6. Nov 11, 2011 #5
    Ok, now you are way over my head. Where can I get info to learn about 'waves on a short transmission line'?
     
  7. Nov 11, 2011 #6

    sophiecentaur

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    Sorry. But you could appreciate that two masses and two springs could be a simpler problem than your original one.
    It's a matter of writing an equation to describe the situation and then solving it. Easy if you say it quickly! Haha
    It's the basics of all wave transmission theory.
     
  8. Nov 11, 2011 #7

    sophiecentaur

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    http://www.ph.biu.ac.il/~rapaport/java-apps/spring.html" [Broken] is an animation which will give you an idea of what I'm describing. You can build a system of two springs and three masses in a line (not what you actually wanted but it's a start) and you can see what happens to the mass at one end when you twitch the mass at the other end.
    You can extend this to what happens when one mass happens to be huge (a wall).
    Have a look ands see if it helps.
     
    Last edited by a moderator: May 5, 2017
  9. Nov 14, 2011 #8
    Sophie,
    Thanks for the link. I went to it and played with the mass and springs which gave me a better understanding of the physics involved. I also sent an email to the creator of the site to see if he would be able to add gravity to it. That would really be a help!
     
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