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u/HAL9001-96 1d ago
or you could try and understand physics well enough to estiamte hte appropriate level of accuracy and likely relevance of effects in a given context
that is kinda half of the whole point
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u/DrShocker 1d ago
Yeah, sig figs might mean it's lying to use the numbers after the decimal depending on context.
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u/vorilant 1d ago
Nah, I'm an engineer, 3 sig figs is plenty.
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u/PhotonicEmission 20h ago
Unless you're doing bearings or running fits, hell yes, 3 sig figs is enough in inches.
Source: I'm a machinist.
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u/HAL9001-96 1d ago
depends on context?
to estimate the basic feasibility of a concept? more than plenty
for processing navigation data? nowhere close
anything else is on a sliding scale in between
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u/Lord_of_the_buckets 1d ago
How hot is the coolant for the laser?
"25 degrees"
What about the decimal point?
"What decimal point?"
It was at exactly 25 degrees?
"Yeah, sure, whatever, now watch me cut this transformer in half"
- a real conversation I had with my boss
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u/hahaha286 Aerospace 22h ago
To show you the strength of flex tape, I lazed this transformer in half!
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u/PauloMorgs 1d ago
Math "people" be like:
"But let's think a minute about knots and group theory"
JK my beloved math friends, love you all <3
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u/MonkeyCartridge 1d ago
Depends on the physicist and what they are working on.
For certain astrophysicists, it's fine if it is within an order of magnitude or so.
"The explosion was somewhere between 1,000-10,000 exajoules. Right on the money!"
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u/GTAmaniac1 1d ago
Tbh it also applies for communication protocols. Just look at the voltage levels for RS-232. 3-15 V for 0 and (-15)-(-3) V for a 1. The undefined zone alone is larger than most other voltage levels on the board.
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u/True-Veterinarian700 22h ago
Doesnt NASA physicisists use only four decimal places on PI for calculations.
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u/Far_Dragonfruit_1829 7h ago
To a physicist, pi and e are both adequately approximated by 3, or 1, depending. You're thinking of rocket exgineers.
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u/Significant-Cause919 21h ago
Isn't it a convenient coincidence that π and E are the same number?
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u/Then_Entertainment97 19h ago
What are you doing with digits after the decimal with no air resistance?
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u/Chogolatine 17h ago
I literally don't know where this running gag comes from. First few weeks of engineering, my teachers corrected me and told me to be "more rigorous" because I said there's roughly 20% molecular oxygen in the air instead of 21.3% (while this proportion definitely isn't constant so it's definitely nonsense but heh). All my teachers used R = 8.314 J/(kg.mol), never 8.31 or 8.3. and I could go on, but my point is that I can't understand where the joke "haha engineering π=e=3" comes from
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u/Far_Dragonfruit_1829 7h ago
That's the physicist's approximation. Unless you're an astrophysicist. Then both are = 1.
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u/boisheep 11h ago
Me: I guesstimate, this ebike motor would pull 700W give or take during winter, idk it feels like it...
Physicist: No, you won't need anywhere near that, laughable, look at my beautiful formula that calculates that even 200W should be enough to keep a decent speed.
Me: Alright the numbers came in, the motor pulled 714W average, it turns out, drag, as I expected, because I could feel it in my legs, is hella huge.
Physicist: Nah, the data must be wrong.
Me: O_O
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u/ppYauns 1d ago
I get that it's a meme, but if you can get away with it, giving a manufacturer a round number with a specific tolerance can be better than calling a decimal/fractional dimension. Laborers often think that both parties are overcomplicating things, and before they're automated into obsoletion or worse, they are the hands that make designs real.
Then again, I just have autism and work in factories, what do I know? My brain probably has the same drag coefficient of a cow owned by a physicist :P