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There’s a pretty good chance your keys would just float up past you if you tried to throw them, and hit the water long after you. I think humans have a higher w

by dahart 5y ago

There’s a pretty good chance your keys would just float up past you if you tried to throw them, and hit the water long after you. I think humans have a higher weight to surface area ratio. But if you found a waterfall, you might try to land in the area that’s bubbling up. That could conceivably improve your chances when hitting water, which are very slim - hitting water in free fall is not that much better than hitting concrete. Trying to execute a stand-up 2 or 3 seconds before impact might help you survive, I could buy that. I’d guess this is something that’s difficult to do without having tried it before, it usually takes a few tries to do without flopping back to flat.

LorenPechtel 5y ago
Would changing your orientation even matter? Wouldn't you just reach the new terminal velocity by the time you entered? It's not like your a Starship that can flip at the last moment and has a big difference between sideways and vertical terminal velocity.
- dahart 5y ago
  I think orientation does matter, and that a water entry might be more survivable with a vertical entry. Think about diving from a high-dive versus a belly flop. At terminal, you’re still likely to break legs or die from entry in a vertical position, but the surface area hitting the water is a lot less if you’re feet first, plus you’d have shoes on, etc. Check out the world record cliff jump https://www.dailymotion.com/video/x32e3od https://www.dailymotion.com/video/x32e3od Terminal in stand-up is indeed much higher than terminal in the flat position. A perfect stand-up / head-down is around 180mph typically, while flat is around 120mph, give or take depending on body shape & density. But it takes time to accelerate, long enough that I think if you stood up quickly you’d still be around the flat-position velocity. The maximum you can theoretically accelerate is about 22 mph/s, but you’re starting from terminal with tons of drag, so I think it would take 5-10 seconds to reach 180mph, and you can go from flat to stand-up in 1-2 seconds.

by dahart 5y ago

LorenPechtel 5y ago

Would changing your orientation even matter? Wouldn't you just reach the new terminal velocity by the time you entered? It's not like your a Starship that can flip at the last moment and has a big difference between sideways and vertical terminal velocity.

dahart 5y ago
I think orientation does matter, and that a water entry might be more survivable with a vertical entry. Think about diving from a high-dive versus a belly flop. At terminal, you’re still likely to break legs or die from entry in a vertical position, but the surface area hitting the water is a lot less if you’re feet first, plus you’d have shoes on, etc. Check out the world record cliff jump https://www.dailymotion.com/video/x32e3od https://www.dailymotion.com/video/x32e3od Terminal in stand-up is indeed much higher than terminal in the flat position. A perfect stand-up / head-down is around 180mph typically, while flat is around 120mph, give or take depending on body shape & density. But it takes time to accelerate, long enough that I think if you stood up quickly you’d still be around the flat-position velocity. The maximum you can theoretically accelerate is about 22 mph/s, but you’re starting from terminal with tons of drag, so I think it would take 5-10 seconds to reach 180mph, and you can go from flat to stand-up in 1-2 seconds.