wow, I hope those kids are strapped in well.
rock leaves his hands at 4 seconds, sound of hit is at 20 sec, that might be far enough to have to factor in the speed of the sound coming back, and zzzz…
Not sure if i have a math predilection or postdilection, but anyway,
s = 1/2 a t^2 + v0 t + s0, if i recall my physics (and calculus) formula correctly, where s = distance traveled, a = acceleration, t = time elapsed, v0 is initial velocity, and s0 is initial position. Also, you have to establish a coordinate system and make sure units are mutually consistent.
To not deal with negative signs, let’s take the origin (zero) for distance s0. at the point where the spelunker releases the rock (or stale pound cake or whatever it was) and downward as the positive direction vertically.
For values of the parameters, assume a = g (the acceleration due to gravity) = 32.2 ft/sec^2 though that can vary over the earth’s surface (or interior), the initial velocity v0 is zero (though the guy did seem to impart a bit of downward push to it, and that can build up over time – especially a long one as we see here). i didn’t time it, but the video elapsed approximately from 4 to 19 on the timer bar, from throw to sound return (which might have taken a second or two, depending on speed of sound which can vary with temperature, humidity, and any wind). So there is a lot of ? or “slop” (also know by the technical term SWAG) in the numbers i’m using. But
s = 1/2 a t^2 + v0 t + s0
= 1/2 (32.2ft/sec^2) (15sec)^2 + (0ft/sec) (15sec) + 0 ft
= 3,622 ft, or about 0.688 mile, a considerable distance in whichever units.
Due to the various caveats i mentioned concerning my assumptions, the actual distance is probably 10-20% less, since my assumptions would have increased the distance in the calculation somewhat.
Did the video itself mention the distance of the abyss or at least where it is located, for reference, so i can grade myself on my decades-old recollection and my interpretation of the parameters?
Maybe somebody can audit my work above. @felton10, you have experience with audits and maybe your two degrees can help here?
@phendrick Just realized most on Meh won’t be familiar with the term “SWAG” the way i meant it and it won’t be given in std dictionaries.
in various technical circles it stands for Scientific Wild-Ass Guess
(Ask a physicist or engineer.)
@phendrick Above my pay grade. People assume accountants are good at math. Take away my adding machine and I have to count of my fingers and toes like everyone else.
@phendrick My well-thought-out and precisely calculated formula wild-ass guess is slightly below yours.
Figuring normal outside air pressure/humidity/gravity and laws of physics, a rock will fall 2700 feet in 12.96 seconds, and the sound will travel the distance back in 2.46 seconds. So you would hear the sound in 15 seconds and a bit. That’s close to the time in the video, under who-knows-what temp, pressure, humidity, or initial altitude.
So calculating differential (mumble, mumble) and adjusting for (indeciferable) and carrying the remainder, I get: “That sucker likely dropped a good half-mile, but prolly less than six-tenths of a mile.”
about 0.688 mile, a considerable distance in whichever units. Due to
the various caveats i mentioned concerning my assumptions, the actual distance is probably 10-20% less
so you and i do agree within my est. margin of error.
Guess that you and i would have made good lab partners.
Always thought the most creative (and instructive) aspects of physics labs was on the lab report trying to explain away why the observed results seemed to NEVER match the predicted theoretical ones.
And then, as a lab assistant, and later lab instructor, i would have chuckled at yours and given it an “A”.
@phendrick I’ll take it! I haven’t been in a physics (or chemistry) lab in 55 years, so I’m surprised I could even remember any of it. You wouldn’t want me in your lab. I break things.
Throwing rocks down the drop damages the cave environment and can kill anything that lives down there that is in the way. If water flows through there it can change how that flows.
wow, I hope those kids are strapped in well.
rock leaves his hands at 4 seconds, sound of hit is at 20 sec, that might be far enough to have to factor in the speed of the sound coming back, and zzzz…
Not sure if i have a math predilection or postdilection, but anyway,
s = 1/2 a t^2 + v0 t + s0, if i recall my physics (and calculus) formula correctly, where s = distance traveled, a = acceleration, t = time elapsed, v0 is initial velocity, and s0 is initial position. Also, you have to establish a coordinate system and make sure units are mutually consistent.
To not deal with negative signs, let’s take the origin (zero) for distance s0. at the point where the spelunker releases the rock (or stale pound cake or whatever it was) and downward as the positive direction vertically.
For values of the parameters, assume a = g (the acceleration due to gravity) = 32.2 ft/sec^2 though that can vary over the earth’s surface (or interior), the initial velocity v0 is zero (though the guy did seem to impart a bit of downward push to it, and that can build up over time – especially a long one as we see here). i didn’t time it, but the video elapsed approximately from 4 to 19 on the timer bar, from throw to sound return (which might have taken a second or two, depending on speed of sound which can vary with temperature, humidity, and any wind). So there is a lot of ? or “slop” (also know by the technical term SWAG) in the numbers i’m using. But
s = 1/2 a t^2 + v0 t + s0
= 1/2 (32.2ft/sec^2) (15sec)^2 + (0ft/sec) (15sec) + 0 ft
= 3,622 ft, or about 0.688 mile, a considerable distance in whichever units.
Due to the various caveats i mentioned concerning my assumptions, the actual distance is probably 10-20% less, since my assumptions would have increased the distance in the calculation somewhat.
Did the video itself mention the distance of the abyss or at least where it is located, for reference, so i can grade myself on my decades-old recollection and my interpretation of the parameters?
Maybe somebody can audit my work above.
@felton10, you have experience with audits and maybe your two degrees can help here?
@phendrick That’s some good stuff there. It’s pretty much a series of beeps to me, but at damn impressive series of beeps!
@phendrick Just realized most on Meh won’t be familiar with the term “SWAG” the way i meant it and it won’t be given in std dictionaries.
in various technical circles it stands for
Scientific Wild-Ass Guess
(Ask a physicist or engineer.)
@phendrick Above my pay grade. People assume accountants are good at math. Take away my adding machine and I have to count of my fingers and toes like everyone else.
@Felton10 Heh. Wish the numbers on my tax returns didn’t get above 20.
@phendrick @shahnm Surprised to find the term actually has an entry in wikipedia.
https://en.wikipedia.org/wiki/Scientific_wild-ass_guess
Maybe i shouldn’t have been. Sometimes looks like people and/or the a.i. bots have a lot of time on their hands and have gone wild there.
The term was prevalent in my college studies more than 50 years ago!
@phendrick My
well-thought-out and precisely calculated formulawild-ass guess is slightly below yours.Figuring normal outside air pressure/humidity/gravity and laws of physics, a rock will fall 2700 feet in 12.96 seconds, and the sound will travel the distance back in 2.46 seconds. So you would hear the sound in 15 seconds and a bit. That’s close to the time in the video, under who-knows-what temp, pressure, humidity, or initial altitude.
So calculating differential (mumble, mumble) and adjusting for (indeciferable) and carrying the remainder, I get: “That sucker likely dropped a good half-mile, but prolly less than six-tenths of a mile.”
@rockblossom @shahnm i did postulate
so you and i do agree within my est. margin of error.
Guess that you and i would have made good lab partners.
Always thought the most creative (and instructive) aspects of physics labs was on the lab report trying to explain away why the observed results seemed to NEVER match the predicted theoretical ones.
And then, as a lab assistant, and later lab instructor, i would have chuckled at yours and given it an “A”.
@phendrick I’ll take it! I haven’t been in a physics (or chemistry) lab in 55 years, so I’m surprised I could even remember any of it. You wouldn’t want me in your lab. I break things.
@rockblossom
… and then blossom?
@phendrick Now you understand my username.
Also, surprised the cave monsters at the bottom didn’t catch and return fire!
/showme cave monsters at the bottom
/showme cave monsters at the bottom being clubbed by a large falling rock
@mediocrebot ooh, i should’t have looked at that right before turning out the light and going to bed!
Them are some big dust mites and bed bugs there.
/showme the balrog
That scenario makes me nervous just seeing the video. Spelunking is never going to be a hobby for me. No way.
@werehatrack I go spelunking. It can be a a lot of fun and you see things that you’d never see above ground. Some of it is incredibly beautiful.
Throwing rocks down the drop damages the cave environment and can kill anything that lives down there that is in the way. If water flows through there it can change how that flows.
/youtube balrog