Water as unyielding as concrete

Discussion in 'Physics & Math' started by Lilalena, May 13, 2011.

  1. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Surface tension!

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    The "skin" of the water.

    This is non-comparable: wood floats because it displaces its own volume of water (having broken the surface tension) - the "water walkers" don't.
     
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  3. John99 Banned Banned

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    The whole point is that this experiment is meant to be studied from objects moving on their own free fall.

    For that matter an egg can break apart in the air if it is accelerated (artificially - as in a bullet fired) enough.
     
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  5. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Bull. Shit.
    That wasen't a comsideration at all in the OP: it only raised the question of impact velocity.

    Are you now talking about it breaking up under acceleration? Or going back and making my point (again) about it being impact velocity that counts?
    Still waiting for an explanation of "force speed".

    Oh, and please define "artificial" acceleration.
     
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  7. John99 Banned Banned

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    *sigh*...the point is you are not getting an accurate experiment here IF you incorporate (wrongly since the study is specifically about water) artificial propulsion.


    It isnt my job to educate you. That is why there is Google.
     
  8. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Balls: what counts is impact velocity. How it's achieved is irrelevant.

    In other words you're doing your usual trick: talking bollocks and then evading when asked to substantiate.
    Inventing your own terms doesn't make you appear clever, it just shows you up as the fool you are.
     
  9. John99 Banned Banned

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    My egg comparison is the deal breaker. Egg breaks at a certain velocity traveling through the air yet an egg traveling through the air at free fall will never break even if dropped from thousands of feet.
     
  10. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Wrong.

    Pardon?

    In other words, again, it comes down to velocity...

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  11. John99 Banned Banned

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    Right so how are you going to get a bullet, traveling at free fall, to have a higher velocity of a bullet fired from a .45 caliber slug just leaving the muzzle?

    Then we may as well throuw the whole experiment out the window and do what ever we want to obtain the results we want. This is fine if you dont mind cheating.
     
  12. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Er, who said we could? How does that have any bearing whatsoever on the question?
    Tell me, have you read (and understood) this thread or have you just dropped in to post inane rubbish and specious comments?

    Please, stop talking out of your arse and at least try to stay on-topic.
     
  13. KilljoyKlown Whatever Valued Senior Member

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    The wood floats on water because it's less dense than the water and air is less dense than the wood. Although the bugs might be less dense than water it's the surface tension that allows them to get around on the water as well as they do.

    No John you didn't make a claim about the water being as hard as concrete. I know this thread is fairly long, but you should have read the first couple of pages before jumping in. It's annoying when someone jumps into a thread and talks about stuff that's already been discussed in depth.
     
  14. wynn ˙ Valued Senior Member

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    I think he was talking about F = m a (force is mass x acceleration).
     
  15. John99 Banned Banned

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    Wow...:facepalm: Discussing things with you is like talking to handball.

    Showing you an error is off topic? Everyhing i posted, including the egg test, is relevant to the OP.
     
  16. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Because you talk nonsense?

    Still wrong. As usual.
    You didn't "point out an error" at all.

    @ Signal
    He still hasn't said what the (supposed) difference is between speed and "force speed".
     
  17. John99 Banned Banned

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    It what make the rocket ship go off.
     
  18. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    No. That's thrust (force), causing acceleration.
    "Force speed" is a nonsense term you've invented.
     
  19. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Thank you for exhibiting your ignorance again. It caused me to ponder something: The question I am contemplating is: Does Archimedes principle still apply? "Weight of the displaced water is equal to the weight of the supported object."

    I think it may not exactly apply, but I am not completely sure. I.e. if all six (assuming the bug is an insect) "dimples" /depressions in the water / were filled with water to make the surface level again would that "filling in water" have exactly the weight of the bug?

    Here is my argument for why Archimedes’s principle may fail:

    A drop of detergent added shows there need not be any fixed relationship between the surface tension and the density of the liquid. If the surface tension were higher, then definitely the dimples would not be as deep. That initially makes me think that less mass of water might be displaced, but perhaps the "Outer radius" of the dimple is increased? Keeping the mass of water displace an invariant (for given bug) with strength of surface tension.

    Anyone have good argument either way? I.e. Is the bug violating Archimedes’s principle of not?

    PS - For floating wax cube or ice cube, etc. it does not exactly apply because of surface tension. I think water wets and ice cube so effectively surface tension make it displace a little more than it weight of water but does not wet a wax cube so surface tension helps it float with less water displaced. In the bug's case it probably comes down to the question: Does the water wet the hairs on the bottom of the bug's legs?
     
    Last edited by a moderator: May 30, 2011
  20. John99 Banned Banned

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    Right....six of one, half dozen of the other.
     
  21. John99 Banned Banned

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    Wow, that is the smartest thing i ever heard you say.
     
  22. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Er, no.
    Inventing your own terms, and dropping them in to a discussion without explanation is stupid, especially when there are readily understood ones for the concept.
    Force is force. "Force speed" is a meaningless phrase that you used, and failed to explain.
    Speed of impact is what is under consideration here.
     
  23. wynn ˙ Valued Senior Member

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    Acceleration is a concept that is difficult to comprehend for many people ... force too, actually.
    Not that it excuses anyone, but it is something science teachers struggle with how to explain to students.
    Hm.
     

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