this post was submitted on 11 May 2024
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Science Memes

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Speed (mander.xyz)
submitted 7 months ago by [email protected] to c/[email protected]
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[–] [email protected] 86 points 7 months ago (3 children)

1.) 0.28 g 2.) 15.7 g 3.) 0.0034 g

I assumed 1m radius for the first and 5m for the second, particularly the second sounds off. Anyway... The centripetal force from Earth's rotation is quiet negligible compared to its gravitation.

[–] [email protected] 34 points 7 months ago (1 children)

The 100 km/h seems a bit much to me, too, but I'm having a hard time finding info on the speed of these...

[–] [email protected] 34 points 7 months ago* (last edited 7 months ago) (2 children)

Looked up a video of a gentle one. A revolution takes about 2𝜋 seconds, at which the speed in m/s is the same as the radius in meters, or around 5. Multiply by 3.6 to convert into 18 km/h, which seems realistic for the milder ones. The apparent horizontal centrifugal acceleration will then be 𝑣²/𝑟 = 5 ms⁻² ≈ 0.5𝑔, which corresponds to an angle of approx. 26° from the verical, reasonably close to the video.

The one depicted in the image probably goes about 2x as fast, pulling perhaps 2𝑔 horizontally for an angle of approx. 63°.

[–] [email protected] 13 points 7 months ago (1 children)

Damn he mathed all over them

[–] [email protected] 4 points 7 months ago

I'd let them math all over me anytime 👌😩🧮

[–] [email protected] 6 points 7 months ago* (last edited 7 months ago) (2 children)

How does one count in π • seconds?

[–] [email protected] 12 points 7 months ago

It's about 6.5 seconds in the video. I rounded that to 2𝜋 so I could do the math in my head (other than the tan⁻¹(0.5), of course)

[–] [email protected] 9 points 7 months ago

"One, two, thr- pi"

[–] [email protected] 34 points 7 months ago (1 children)

5 meters is definitely way too short for the chair swing ride. Look at the people in the seats. It's definitely at least 10 meters.

Assuming 10 meters and 100 km/h, that gives about 7.9 g. That's in the range of what fighter pilots might experience and well beyond where most people black out, so that's still definitely too high.

Looking it up online, this is a pretty classic physics problem and the numbers you might see around it are closer to a radius of 12 meters and a speed of 13 to 17 m/s. Taking that as 15 m/s (54 km/h), that works out to about 1.9 g, which I can subjectively say feels much closer to the real value if you ever ride on one of these.

So, the second one is about 1.9 g

[–] [email protected] 4 points 7 months ago

Yeah, those rides complete a rotation in ~10 seconds given what I was able to count in a couple YouTube videos, so 36°/sec. If they have a 10m radius, the linear velocity would be 6.283 m/s or 22.62km/he.

[–] [email protected] 18 points 7 months ago (1 children)

Considering most people will start to lose consciousness and risk heart issues at like 5g, I’m pretty sure the speed is way off on number 2.

[–] [email protected] 13 points 7 months ago (1 children)

That’s what the juice is for, inyalowda

[–] [email protected] 2 points 7 months ago

The juice is inner conspiracy, sassa.

Killed Fred Fucking Johnson in his couch.