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B Instantaneous Speed of Gravity Experiment

  1. May 4, 2018 #1
    I 22196011_339247773201642_4832317612364782148_n.jpg n ordinary weighing scale, in left pan, there is spiral shaped coil (like that mosquito coil) or any long shaped rod. Middle point of this coil is touching the left pan. Let mass of this coil be W1. Second body of mass W2 is attached to other end of this coil. So the left pan is experiencing total weight W1+W2. In right pan, there is mass M3 which mass is equal to W1+W2. So both pans are at same level from ground.

    Now we remove weight W2 attached to coil. Info regarding removal of weight W2 travels to pan through spiral coil W1 in time t. During this delay t, left pan still experiences total weight W1+W2. If we put weight W2 - which is in our hand - on the left pan during this delay t, then pan will experience total weight W1+W2+W2 which is greater than W3 in right pan.

    So obviously left pan will come down and right pan will go up during this propagation delay t.

    That means we have created excess energy and law of conservation of energy is broken. Am I right?
     
    Last edited by a moderator: May 4, 2018
  2. jcsd
  3. May 4, 2018 #2

    fresh_42

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    Just a remark: We don't want to discuss perpetual motion machines, but explanations where missing energy is hidden are o.k.
     
  4. May 4, 2018 #3

    russ_watters

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    So per the previous post, it is better to ask "where did the missing energy go?"

    The answer is that it is spring energy in the rope.
     
  5. May 4, 2018 #4
    Missing energy? Can you please explain what you are saying? And I have devised this experiment to show that speed of gravity is instantaneous. If it is not instantaneous, then its finite speed can be used to create excess energy. It doesn't mean that I am discussing "free energy". I am discussing instantaneous speed of gravity.
     
  6. May 4, 2018 #5

    russ_watters

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    Actually, you never mention a speed of gravity in your post, so it isnt clear how you could conclude anything about it from what you described.

    But in either case, you are stating that there are two possible conclusions, and there aren't: there are three:

    1. Finite SOG=excess or missing energy.
    2. Infinite SOG=no excess or missing energy.
    3. There is energy somewhere else that isnt accounted for in #1.

    And #3 is the answer, and the experiment doesn't tell us anything about the speed of gravity. Why? because you are transmitting the force via mechanical interaction in the rope, not via gravity.

    Have you looked at the real experiments used to show the speed of gravity? Mercury's orbit precession?
     
  7. May 4, 2018 #6

    Nugatory

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    There is some amount of potential energy stored in the spring because it is under tension from supporting W2. When you remove W2 the spring relaxes, releasing that potential energy to push the left-hand pan down and raise the right-hand pan.
    No excess energy has been created; you've just used the potential energy in the spring to displace the pans.

    Nor is this a measure of the speed of gravity, as gravity is acting on all parts of the system at all times. It's just that during the very short period of time after you've removed W2 from the spring, there is a force other than gravity, namely the force from the relaxing spring, that is also acting on the left-hand pan.
     
    Last edited by a moderator: May 4, 2018
  8. May 4, 2018 #7
    The system is not big to raise "somewhere" doubt. Let us make this system more simple. Our weighing scale consists of simple horizontal rod supported in the middle by vertical pointed rod. Let us remove pans also and place spiral coil (W1+W2) on left side of this horizontal rod and W3 on right side of this rod. Let length of this horizontal rod be less than length of spiral coil (W1). Now where exactly your missing energy is stored in this small system?
     
  9. May 4, 2018 #8

    A.T.

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    Any real world rod is not perfectly rigid, so it can store elastic energy when deformed.
     
  10. May 4, 2018 #9

    russ_watters

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    Exactly the same place as where it was before: in "spring energy" (elastic energy).

    The problem with your experiments is that you are making your devices interact mechanically and then claiming it says something about gravity. If you want to say something about gravity, you have to test gravitational interactions!

    Try this instead:
    Two pendulums, suspended from the ceiling, some distance apart. Gravitational interaction pulls them together by some amount. Now grab one and yank it away. Does the other one move away instantly or not? If not, what does this say about conservation of energy/speed of gravity?
     
  11. May 4, 2018 #10
    The left hand pan has no information (as per current theory) during propagation delay t. That means no matter what you do at W2 point, the left pan will not feel anything. That means it will not push down anything. And I am taking advantage of this propagation delay. I removed W2. Left pan has no information about event happened at other end of spiral coil during propagation delay t. I removed W2 and put down it on left pan during t. (Note that you can shift position of W2 from coil to left pan just by sliding it)
     
  12. May 4, 2018 #11
    I haven't understood what you mean by "missing energy" and "spring energy". All materials -gas, liquid and solid- can be visualised as made of springs. In this system also spiral coil W1, body W2 and weighing scale (horizontal rod) etc are can be visualised as made of springs. But I simply don't understand what you mean by " missing energy" and "spring energy".

    And gravity is not the thing scientists (and hence everyone) visualise. That is why no one till date could devise any logic and experiment to measure speed of gravity.
     
  13. May 4, 2018 #12
    (Imagine me raising my both hands in confusion and asking) What? That everybody knows.
     
  14. May 4, 2018 #13

    Mister T

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    If you have a certain amount of energy in a system now, and then later on the amount is less than it was before, the difference is the "missing energy".
    Example: A system has 13 J of energy now, then later it has 11 J, the missing energy is 2 J.

    You have an object and you apply a force to deform it. When you stop applying the force the object returns to its original shape. The work done by that force is equal to the "spring energy".
    Example: A rope has a length of 20.00 meters. A force is applied, stretching the rope to a length of 20.01 meters and doing 3 J of work. The "spring energy" stored in the stretched rope is 3 J.
     
  15. May 4, 2018 #14

    russ_watters

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    Conservation of energy statements look like this:

    Ein=Eout

    Ebefore=Eafter

    delta-E=0

    If you apply a conservation of energy equation and the result is unequal then there is an error in it. And the error can either be that you have too much energy on one side ("excess", as you said) or not enough on the other ("missing", as I said). In your prediction of how this experiment behaves, you have missing energy.

    I think you kind of know this and are trying to use this method to prove the error that causes the excess energy is due to the propagation speed of gravitational interactions. But you aren't correct: you don't have extra energy that could point to the finite speed of gravity being wrong, but rather there is energy you didn't consider - missing energy - in your experimental setup and analysis.
    You seem to understand it pretty well, but maybe just aren't aware of the result that stretching or contracting springs stores energy:
    https://en.wikipedia.org/wiki/Elastic_energy

    This is the energy that is being released to move the balance pan when the weight is removed. Not gravitational force/energy.

    And you should be able to figure this out logically, since your experimental setup doesn't actually require gravity at all. You used gravity as a roundabout way to apply a force to the balance pans, but you didn't need to, because gravity itself does not act on the pans. The pans are being physically pushed by the weights. So if you replace the weights with literally anything that can apply a force (more springs, cables, pistons, your finger), you eliminate gravity from the experiment and it produces the exact same result.
    Are you saying you understand how gravity works and scientists don't? Because that's a pretty arrogant statement and the type of thing we don't allow here and this thread will have to be locked if that's what you are after. Are you even aware that scientists do in fact conduct experiments to see if there is a speed of propagation of gravity? You aren't wrong to want to investigate this, it's just your experiment doesn't work and you don't seem to care. You'd be better off recognizing that it doesn't work and looking at other experiments that do.
     
    Last edited: May 4, 2018
  16. May 4, 2018 #15

    russ_watters

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    Combining the two: if you apply 13 Joules to compress an object and get back 11 Joules when it expands again, you now have 2 missing Joules that need to be accounted for somehow. In my example here, the diference may be heat dissipation, plastic deformation, etc.
     
  17. May 4, 2018 #16

    Mister T

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    Right. The point being that if the energy of the system decreases by 2 J then the energy of the environment must increase by 2 J.
     
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