Comment on Stress

• azi@mander.xyz ⁨6⁩ ⁨months⁩ ago

  mm/mm?? why not call it m/m?

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  • captainlezbian@lemmy.world ⁨6⁩ ⁨months⁩ ago

    Because we’re precise!

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  • Umbrias@beehaw.org ⁨6⁩ ⁨months⁩ ago

    Because practicality. Strain generally occurs across mm scales at most for most traditional tensile tests and relevant materials. Normally it’s actually much less than mm. Occasionally you see micrometers/micrometers.

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    • azi@mander.xyz ⁨6⁩ ⁨months⁩ ago

      How is it more practical when 1 m/m = 1 mm/mm = 1 μm/μm?

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      • Umbrias@beehaw.org ⁨6⁩ ⁨months⁩ ago

        Because excel doesn’t have built in unit handling so when you enter in readings from the strain gauge you’ll probably enter them in what’s being reported.

        You can write the units of strain however you like, I often say ul for unitless.

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      • nooneescapesthelaw@mander.xyz ⁨6⁩ ⁨months⁩ ago

        The original specimens and data are usually in mm, not meters so mm/mm makes more sense than m/m, although you do have a point

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  • bleistift2@feddit.de ⁨6⁩ ⁨months⁩ ago

    Why km/h (or mph) and not ft/year? Because the numbers have a nicer magnitude then.

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    • nooneescapesthelaw@mander.xyz ⁨6⁩ ⁨months⁩ ago

      Doesn’t apply here, say for example i have a piece of steel with length 100mm and it stretches 10mm, is mm/mm the strain would be 0.1 mm/mm, in meters it would be 0.1m/m

      Really strain is dimensionless but occasionally people add units

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      • bleistift2@feddit.de ⁨6⁩ ⁨months⁩ ago

        I feel like I should’ve spotted that… they’re the same units. 🤦

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• iAvicenna@lemmy.world ⁨6⁩ ⁨months⁩ ago

  I was told that you also sometimes have four basis vectors in 3D

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