Originally published at: http://boingboing.net/2016/10/12/skydiver-loses-then-retrieves.html
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Can someone who knows more about parachuting than me explain how this is possible?
He loses his shoe. Shoe continues to accelerate towards ground at roughly 9.8 ms-2. He has an open chute, so his downwards acceleration is presumably significantly less.
How does he catch up with the shoe?
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I haven’t seen the video, but if it came off immediately after he left the plane, it would have probably had a lower terminal velocity than him, because it was tumbling.
So when he pulled the chute, the shoe was above him.
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That makes more sense.
Follow-up question (and please forgive my ignorance): why does tumbling decrease terminal velocity? I assume it’s something to do with drag, but why would that be greater with a tumbling object than with one with its broadest surface perpendicular to the direction of travel?
Terminal velocity is a function of weight divided by drag - running shoes aren’t very dense; in fact they seem about on par with a person hanging from a parachute.
I don’t think the tumbling has a whole lot to do with it, other than precluding the shoe from finding its most aerodynamic attitude.
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Thank You For Not Littering™
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Physics glanced at Arthur, and clotted with horror he was gone too, sick with giddy dropping, every part of him screaming but his voice.
They plummeted because this was London and you really couldn’t do this sort of thing here.
He couldn’t catch her because this was London, and not a million miles from here, seven hundred and fifty-six, to be exact, in Pisa, Galileo had clearly demonstrated that two falling bodies fell at exactly the same rate of acceleration irrespective of their relative weights.
They fell.
Arthur realized as he fell, giddily and sickeningly, that if he was going to hang around in the sky believing everything that the Italians had to say about physics when they couldn’t even keep a simple tower straight, that they were in dead trouble, and damn well did fall faster than Fenchurch.
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Surprised it wasn’t an Air Jordon.
I’ll see myself out.
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I was nodding my head reading your post, but then I watched the video and it looks like this is not the case. He jumps out of the plane with someone else holding him, I’m not sure but it looks like this second person pulls his shoe off and lets it go maybe 30 metres below him, with the first person’s chute already deployed or deploying.
I guess then that a shoe has a relatively low terminal velocity. The skydiver seems pretty experienced, and it looks like he’s working his controls pretty hard to be able to fall as fast as the shoe.
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“Hapless” skydiver?
You keep using that word. I do not think it means what you think it means.
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To be sure, he had a lot more ‘hap’ once he got his shoe back. Seemed downright happy, in fact.
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