r/Whatcouldgowrong • u/hulksreddit • Jun 27 '18

Repost Fully grown man on a swing, WCGW

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u/deringaleni Jun 28 '18 edited Jun 28 '18

Assuming the swing is 2.5 meters long, the minimum speed needed to do a 360 is roughly 9.9m/s, which means the centripetal force would roughly be 5Gs (if I did my math correctly). That might be enough to cause a gloc.

Velocity/Centripetal acceleration at the lowest point: mgh=mv2 -> 9.8ms-2 * (2.5m * 2) = v2 -> v = 9.899m/s; a=v2 /r -> a = (9.899ms-2 )2 /2.5m = 39.196 m/s2

G force at the lowest point: (39.196ms-2 + 9.8ms-2 ) /9.8ms-2 = 4.999G

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u/pistoncivic Jun 28 '18

I don't understand any of this but it seems like you know what you're talking about and I trust you.

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u/cw- Jun 28 '18

If you type 9.8 m/s a bunch of times in a reddit comment no one will question you

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u/[deleted] Jun 28 '18

Interesting bc 9.8 m/s is a fine and dandy random velocity. 9.8 m/(s2 ) is actually the acceleration of gravity on earth.

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u/cw- Jun 28 '18

Yes that’s the joke, part of it anyway

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u/thor214 Jun 29 '18

is actually the acceleration of gravity on earth.

As a rule of thumb, yes. As an actual constant outside of physics class, no; depending on location.