Vibratory System

Discussion in 'Hydrodynamics and Aerodynamics' started by gonzo, Jul 25, 2018.

  1. gonzo
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    gonzo Senior Member

    Newton's third law states that for every action (force) in nature there is an equal and opposite reaction. That means that the action of a horizontal force creates an equal horizontal reaction of opposite direction. It can't generate a vertical force to lift a body.
     

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  2. MikeJohns
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    MikeJohns Senior Member

    Gonzo, you are very creative ! I was the member that made the post you are misrepresenting :

    Following which you decided it was a vibration not a complex dynamic system as I tried to explain to you.

    And here we are.
     
    Last edited: Aug 5, 2018
  3. MikeJohns
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    MikeJohns Senior Member

    Basic Vector addition ? Start by considering the simplest machines. So long as the inline sum of the vectors are equal Newton remains happy.
     
    Last edited: Aug 4, 2018
  4. Barry
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    Barry Senior Member

    One example of a horizontal force lifting an object. Assume the pulling force is say a light weight
    braid with no ability to create a vertical force and that the force is horizontal throughout its pull.
     

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  5. rwatson
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    rwatson Senior Member

    Oh come on Gonzo - even I can show you that is wrong. A variation of Barrys illustration.
    Uplift.png
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    This thread lacks harmonic balance. :(
     
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  7. Ad Hoc
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    Ad Hoc Naval Architect

    HUH??

    What on earth has a child's balloon demonstrating the effects of a variable mass dynamics got to to with a mooring buoy, like that posted above?
    Barking up the wrong tree again.

    Alice is indeed going further down that hole...
     
  8. gonzo
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    gonzo Senior Member

    That is not a correct free body diagram. Where are the reaction forces. If you balance all the forces, you need to add one horizontal and one vertical. The vertical component is the one that lifts the chain or rope. Think of the buoyancy as the rode pulls down. If there was no vertical component, the boat would sink.
     
  9. gonzo
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    gonzo Senior Member

    That is not correct. The complete diagram, assuming it is oriented to standard x-y and there is gravity, should show a vertical force down from gravity, and a vertical force up from the surface.
     
  10. gonzo
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    gonzo Senior Member

    It is an example that shows that the string acts like a spring as the length changes. It is the same phenomena as the anchor rode lifting from the bottom.
     
  11. Barry
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    Barry Senior Member

    Your absolute comment that states that a purely horizontal force cannot lift an object is what this sketch contradicts. I am well aware that the force of gravity produces a vertical downward force at the block that can produce a vector at 90 degrees to the angle of the incline as well as parallel to the angle of the incline. BUT your comment clearly states that a pure horizontal force CANNOT
    LIFT AN OBJECT is not correct.
    In this sketch, there is no vertical force within the tow line, just horizontal

    RWatsons diagram would have an element of vertical force as it lifts the rode, assume the rode weighs 50 pounds under water, then the vertical force down at each node is 25 pounds
     
  12. gonzo
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    gonzo Senior Member

    The free body diagram is incorrect. A horizontal applied force can only get a horizontal reaction force. The vertical force components are missing in the diagram. The buoyancy of the hull applies a vertical component. They are the forces on the y-axis.
     
  13. TANSL
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    TANSL Senior Member

    Amazing
     
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  14. Ad Hoc
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    Ad Hoc Naval Architect

    No it is not - nothing like it. If you knew what you were talking about - rather than throwing one liners away like they are going out of fashion hoping one of them sticks, you would know this.

    So, the balloon in the kids simple example, rises, the balloon and tails lifts off the ground nothing holding it, so - tell me how this is the same as a buoy that is tethered by its anchor and mooring vessel? The balloon is not tethered.
    Chalk and cheese and you're barking up the wrong tree and cannot even see it.....utter nonsense.

    You realise it is a sTring not a sPring...
     
    Last edited: Aug 5, 2018

  15. TANSL
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    TANSL Senior Member

    I think that saying that he is barking is uneducated and it is not the language that this forum should allow. But perhaps I am wrong in relation to the education necessary to participate.
     
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