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Is this sorta mechanical component ever made?

  1. Feb 5, 2009 #1
    When a force falls on a body, it gets a normal reaction.

    Conventionally this normal reaction can be given by friction, spring compression, chemical reaction, motion etc...

    Now...have we ever made such an arrangement that this normal reaction is derived from the stress on a body...nothing else...or at at least some amount of normal reaction is derived from the stress in the body.

    Just for examples sake...suppose a bomb explodes in a rigid container...all the the shock wave will be absorbed or normal reaction will be given back to that shock wave from the container's reaction to the stress made by the shockwave...or the strength of the container will give the normal reaction. In this case there's no net motion but there's a normal reaction cause of the rigid container (considering a perfectly homogeneous explosion, i.e shockwave completely distributed in space evenly).

    If the explosion would not have been homogeneous, there would have been a net displacement, same for any force applying in one direction

    What I am asking here is...has any arrangement been made so as to derive this normal reaction from the stress in the body even though the force is in one direction and without giving the total arrangement a net motion (small amount of motion is ok).

    If you don't get it pls respond.
     
  2. jcsd
  3. Feb 6, 2009 #2
    I guess not.
     
  4. Feb 7, 2009 #3

    russ_watters

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    You seem to be implying some sort of reactionless propulsion or energy generation. If so, you are misinterpreting the free body diagram of the forces. Internal forces will not ever sum to anything but zero externally on a continuous basis.
     
  5. Feb 7, 2009 #4

    Dale

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    Emphasis Added

    Spring compression is stress. When you place an object on a flat table the normal reaction is due to stress. This happens all the time.

    However, if russ_watters is correct and you are asking about some sort of reactionless propulsion then you really misunderstand stress.
     
  6. Feb 9, 2009 #5
    When you shoot a bullet the force is internal.
     
  7. Feb 9, 2009 #6
    The reaction is to be derived from the internal stress of the body.
     
  8. Feb 10, 2009 #7

    Integral

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    Do you mean like in a bouncing ball?
     
  9. Feb 10, 2009 #8

    cjl

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    Yes. And the forces sum to zero in that case too (hence recoil).
     
  10. Feb 16, 2009 #9
    No...like an explosion in a contained rigid chamber...the reason why its shockwave did not pass though the chamber is cause the normal reaction was given by the chamber.
     
  11. Feb 17, 2009 #10

    Dale

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    So are you just asking if anyone has ever made an explosion in a rigid chamber? If so, the answer is yes.
     
  12. Feb 18, 2009 #11
    :rofl: :rofl: :rofl: :rofl:

    No man!...I used that to explain my point.
     
  13. Feb 18, 2009 #12

    Dale

    Staff: Mentor

    OK, why don't you try a different explanation. I don't think anyone understands your question. A free-body diagram might help more than words.
     
  14. Feb 18, 2009 #13

    russ_watters

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    Agreed. We're only guessing at your point - you are being very vague.
     
  15. Feb 22, 2009 #14
    I believe the OP is attempting a net-unidirectional force through some type of exotic internal manipulation(explosive or otherwise)
    In other words, a forced displacement of the center-of-mass and, more so, in a continuing, net-unidirectional force outcome within a closed-system.

    That's a hard call...
     
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