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Massless String

  1. Nov 16, 2006 #1
    Hi,
    I am new to the forum. lol.
    I came here because in my physics class, many of the experiments call for massless string.

    Does anyone know where I could purchase some?
    I understand it is harder to come by, but I am willing to pay extra.

    Thanks a bunch
     
  2. jcsd
  3. Nov 16, 2006 #2

    jtbell

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    But beware! A massless string must have zero volume and therefore zero diameter, unless there is a substance that has zero density. Therefore an envelope containing a massless string is difficult to distinguish from an empty envelope. :wink:
     
  4. Nov 16, 2006 #3

    Danger

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    Yeah. Someone is either having you on, or using bad terminology.
    The closest thing that I can think of to what you want is actually called 'invisible thread'. Close-up illusionists use it to levitate things like cigarettes or coins. Any magic-supply house will have it in stock.
     
  5. Nov 16, 2006 #4

    arildno

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    We Norwegians sell tons of it to dumb Swedes.
     
  6. Nov 16, 2006 #5

    Danger

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    Just how does one weigh out 'tons' of something with no mass? :confused:
     
  7. Nov 16, 2006 #6

    arildno

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    Good question! But then, you are a Canadian, not a Swede.
     
  8. Nov 16, 2006 #7
    Sad, but true :frown:
     
  9. Nov 16, 2006 #8

    Danger

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    That might explain it...
     
  10. Nov 16, 2006 #9

    BobG

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    Try dental floss. It's strong and has a mass of nearly zero, except for particularly large values of zero.

    It's also works very well to cut cake at parties.
     
  11. Nov 16, 2006 #10

    radou

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    Picturing that really made me laugh. :rofl:
     
  12. Nov 16, 2006 #11
    Are you using a precision microgram torsion balance? If not, all string is massless to within experimental uncertainty. That's what "massless" means in this context.
     
  13. Nov 16, 2006 #12
    lol, if you are looking for string with very insignificant mass, try fishing line or as danger pointed out, magicians string (or whatever you call it). I doubt that the mass of a string is going to ruin your experiments unless you're using shoe laces, and even in that case you could weigh it beforehand and subract it from your experimental data.
     
  14. Nov 16, 2006 #13

    BobG

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    What's so funny about that?

    Measure out the needed length of floss and dip it in a cup of water. Then you can visually lay out your cut, holding the floss over the cake, then lowering it as you slightly bring the string back towards your body. Perfectly straight cuts without that tendency to veer off to one side that frequently happens as you concentrate on the point where the knife is contacting the cake.
     
  15. Nov 16, 2006 #14

    Hootenanny

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    If the poster has access to such a balance I suspect they would not have had to ask the question...:rolleyes:
     
  16. Nov 16, 2006 #15
    I looked at the post thinking it was about string theory!
     
  17. Nov 16, 2006 #16

    BobG

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    I hope your experiment isn't on standing waves on a string. A massless string would tend to complicate your experiment.

    On the other hand, that would provide one way to measure the mass of your string if you lacked a scale of sufficient precision.
     
    Last edited: Nov 16, 2006
  18. Nov 16, 2006 #17

    arildno

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    Why bother about them when we can partake in the glory of the Atwood machine? :confused:
     
  19. Nov 16, 2006 #18

    Moonbear

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    :rofl: :rofl: I think you can buy them at the same place the sells the frictionless pulleys. :approve:

    Oh, and from your username, it seems you'll probably really enjoy our current welcome fish...mackerel! :biggrin:
     
  20. Nov 16, 2006 #19
    Thanks everyone for the help.
    I guess that my precision microgram torsion balance experiments will have to be put on hold.
    For now, floss it is.
     
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