Cliff jump (into water) question

[Calvin19 0]

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Pictures?

Of the cliff jump not the ass.

http://www.facebook.com/album.php?aid=2007456&l=492f0&id=203002032

dont know who you were replying to.

two way is the 80'

me and hobbes are standing on the 'white rock' in the other.

and the freefall BASE was very low, some say it has been cliff jumped, but the same peopl say the whit rock was cliff jumped, even though like i said it would take a dirtbike to clear the talus.

[base736 0]

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Impact force, is directly proportional to speed.

Perhaps (for certain types of "impact"). Damage done in a sudden impact, however, is more closely related to the amount of energy dissipated -- that is, how much energy is available to blow your ass cheeks apart, and how much is left even after that to do the sorts things that water shouldn't do without first buying you a drink. The energy dissipated is given by the kinetic energy at impact, which (as noted above) is proportional to speed squared.

Which is to say, as in a previous discussion, that (for sudden impacts, such as hitting water at high speed) twice the impact force sucks, but twice the impact force over twice the distance sucks even more. The same may not be true of more extended decelerations taking place over seconds.

[VictorSuvorov 0]

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more closely related to the amount of energy dissipated -- that is, how much energy is available to blow your ass cheeks apart

To get really technical, what is relevant here is the "power" of an impact, not "energy", or energy dissipated in a given time period. The amount of kinetic energy dissipated in a water impact is about the same as in a "pavement" impact . (holding the velocity and the mass of the jumper constant) what makes the difference is the amount of time it takes to "decelerate" the body.

[base736 0]

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To get really technical, what is relevant here is the "power" of an impact [...]

Can you support that with a reference of some sort? My understanding has always been that in hard collisions, kinetic energy at impact is the relevant factor, while force is important for more extended collisions.

The rationale goes as follows... As a warning, anybody with no interest in discussing the "why" of that should stop reading now. The below will almost certainly not make you a better jumper.

There is a certain minimum amount of energy involved in, say, breaking a particular bone. Undoubtedly, one can expend more than that to do the same damage less efficiently, but there is some way which takes the least energy, and that minimum is not zero.

For more extended impacts (a proper dive, or a bungee jump, as opposed to landing in a seated position), a lot of mechanical energy is lost to heat, and it's more useful to talk about the force applied to a part of the body (though the above argument still holds).

Either way, a certain amount of energy is required if one wants to break the bonds that keep the bone/spleen/ass cheeks together. You can apply half that amount as quickly, or as cleverly, as you like, making the power arbitrarily high, and it still won't do the trick.

Edit to add: Could be we're basically talking semantics here. It's not clear to me that one could manipulate force and power independently, so that it may be possible to use either in the case of an extended impact.

[Calvin19 0]

damn guys, we are talking about cliff jumping. this is not Apollo. for the most part, all water is the same (assuming salt water, mineral water, etc). and ALL that matters for the impact on water assuming it is still water, is speed. thats it.

[VictorSuvorov 0]

weight?

[HydroGuy 0]

Bunch of wanna be Steven Hawkings around here.

Why don't you guys argue if information is lost upon the demise of a black hole or something while you're at it.

All you need to know about physics is if you hit the ground (or water) hard, it's going to ruin your day.

Later

Get in - Get off - Get away....repeat as neccessary

[460 0]

From Emergency Room statistics, the Life-or-Death 50% distance over water is 90 feet, independent of how the person fell into the water or the type of person who fell into the water. I use the acronym LD for Life-or-Death whereas in some circles it's referred to as Lethal Dose. Anyway, it's 30 feet over concrete.

Looks like a death sandwich without the bread - Steve Deadman Morrell, BASE 174

[Calvin19 0]

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weight?

impact force for the individual would be different because of weight, but the personal relative impact forces would be the same. hmm.... homeslice is right, we should bring the black hole into this.

but we are assuming that the jumpers are all fairly well built kids, not fat, slobby beer belly bitches.

[CReW 0]

Wow, so an average person has a 50% chance of living if they jump into water from 90 feet?
I believe it.
I assume a BIG person will hit the water a lot harder then a small person. Yes,
a small person will slip into the water like butter down a hot tube and a big guy will take quite a beating from the same jump. Better press them buns together and arms nailed to your side when you hit.

Nice pictures Calvin, BASE jumpers always have great pictures.
T

[Calvin19 0]

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Wow, so an average person has a 50% chance of living if they jump into water from 90 feet?
I believe it.
I assume a BIG person will hit the water a lot harder then a small person. Yes,
a small person will slip into the water like butter down a hot tube and a big guy will take quite a beating from the same jump. Better press them buns together and arms nailed to your side when you hit.

Nice pictures Calvin, BASE jumpers always have great pictures.
T

who the hell is comeing up with this shit? 50%?

dont get me started on fat people. just dont.

and arms above your head, covering your junk, or at your side. if wearing a life vest as i sometimes do, arms crossed over chest.

after i was base jumping for a year, and then over the summer went back to the big cliff jumps in MN, i was worried i would mess up exits and impact more face down. but, i guess its like riding a bike. only, scary.

[Calvin19 0]

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From Emergency Room statistics, the Life-or-Death 50% distance over water is 90 feet, independent of how the person fell into the water or the type of person who fell into the water. I use the acronym LD for Life-or-Death whereas in some circles it's referred to as Lethal Dose. Anyway, it's 30 feet over concrete.

I assume you mean, triping and falling. not a controled jump. is there not some russian kids that do close to 10 meter land jumps?

[mtnlion667 0]

I think the russian guy your talking about is this kid:

http://www.youtube.com/watch?v=JEbYtOEftc0&mode=related&search=



but the master of parkour is david belle, and he's french. One bad ass M.F.'n frenchman at that. search him on youtube..... entertain you for hours.

"Faster, faster, until the thrill of speed overcomes the fear of death."
Hunter S. Thompson

[Calvin19 0]

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I think the russian guy your talking about is this kid:

http://www.youtube.com/watch?v=JEbYtOEftc0&mode=related&search=



but the master of parkour is david belle, and he's french. One bad ass M.F.'n frenchman at that. search him on youtube..... entertain you for hours.

not what i was talking about, but thats cool, even though its been posted in every forum everywhere and im sick of seeing it.

i was talking about thebuilding jumpers, the kids that take HUGE jumps from building to building. maybe i was dreaming. i dono. but i have jumped 90', and it pisses me off to think that someone thinks there is a 50/50 chance of liveing theough a jump like that. that means i have cheated death on cliff jumps and won a lot.

was not replying to anyone in particular.

[mtnlion667 0]

That's david belle and Cyril Raffaelli..... I think

in the end of this video
http://video.google.com/videoplay?docid=8970008800328106389

he does a pretty good building to building w/a 2 story drop. if there's cats doing bigger than that, than they've got issues. don't we all though

and don't be pissed off if you're good at cheating death....... i thought that was the point

"Faster, faster, until the thrill of speed overcomes the fear of death."
Hunter S. Thompson

[Calvin19 0]

thats the one! thank you.

and i like your sig line. faster my freind, faster.

[980 0]

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From Emergency Room statistics, the Life-or-Death 50% distance over water is 90 feet, independent of how the person fell into the water or the type of person who fell into the water. I use the acronym LD for Life-or-Death whereas in some circles it's referred to as Lethal Dose. Anyway, it's 30 feet over concrete.

for Calvin's benefit, I assume the above means that 50% of the people admitted to an emergency room after having fallen 90ft into water die.

the emergency room statistics are just that

they do not take into account the people who do not get injured, or get injured but do not make it to the emergency room, or die but do not make it to the emergency room

please correct me if I've gotten this wrong

[Calvin19 0]

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From Emergency Room statistics, the Life-or-Death 50% distance over water is 90 feet, independent of how the person fell into the water or the type of person who fell into the water. I use the acronym LD for Life-or-Death whereas in some circles it's referred to as Lethal Dose. Anyway, it's 30 feet over concrete.

for Calvin's benefit, I assume the above means that 50% of the people admitted to an emergency room after having fallen 90ft into water die.

the emergency room statistics are just that

they do not take into account the people who do not get injured, or get injured but do not make it to the emergency room, or die but do not make it to the emergency room

please correct me if I've gotten this wrong

I can see that.

because if that is true, me and 3 of my MN boys need some scientific testing, and to bust out our contracts with satan, cause we have the best luck of anyone. I bet me and those kids have 200 80-90'rs, the only injury i ever saw was a fat 45 year old lady, (that i know well) she enterered the water about 20 degrees head back, and came up with bruises that appeared so fast, it was scary. LP hospital sees a lot of that we found out.