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- It says kilonewtons...

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And after this video,

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you will have a much better understanding

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than probably 99% of the
rest of the climbers,

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00:00:12,940 --> 00:00:16,010
what these kilonewtons actually mean,

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and what forces are involved
in real climbing falls.

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And then I will explain
why big, big whippers

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are often much softer than small falls.

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But first, let's find out what is force.

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I like to play with my
Instagram followers,

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so I decided to ask them
what comes to their mind

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when they hear the word force.

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Half of the people said

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that it has something
to do with "Star Wars".

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Fair enough.

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And then before you start thinking

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that half of my Instagram
followers are really smart,

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I have to say that majority
of them didn't vote it at all.

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So I imagine something like...

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What is force?

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(lively music)
(electronic buzzing)

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Okay, but those who wanted to sound smart

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said that force is mass
times acceleration,

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which is the formula
that Newton, this guy,

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came up with.

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- [Newton] Ooh yah.

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And that's why we
measure force in Newtons.

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Which to me is a little bit
funny when you think about it,

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imagine Newton.

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(gentle music)

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So we measure mass in kilograms,

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and we measure acceleration
in meters per second squared.

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Then we should measure force in Newtons.

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(clapping)

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So to put this formula into perspective,

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it's like one Newton, this guy,

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is pushing one kilogram of mass

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and that makes that mass to accelerate

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by one meter per second, every second.

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So here I have a carabiner.

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If I put all my weight on it, like so,

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the question is, what's
the force right now

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into this carabiner?

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So if we look back to the formula,

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we can say that mass is my mass

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multiplied by acceleration.

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What acceleration?
I'm hanging on a tree.

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There is no movement,
no acceleration...

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or is there an acceleration?

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(upbeat music)

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Look, so you've probably
seen this experiment before,

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I have heavy object and a light object.

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And the question is, if I let go

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both of them at the same time,

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which one is gonna hit the ground first?

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Let's try.

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So yes, they fell at the same time,

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because that's what gravity does,

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it makes objects fall at
exactly the same acceleration

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of 9.8 meters per second per second.

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So then I'm hanging on this carabiner,

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gravity is pulling me down.

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But in order for me to not move down,

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there must be opposite force,
which would be pulling me up.

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Here I have a spring.

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While the gravity is
pulling the rock down,

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the spring is pulling the rock up.

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So the carabiner is actually
like a very, very stiff spring,

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which is pulling me up.

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The molecules of the carabiner
when I'm hanging on it

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are being spread apart,

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but they like to stay
together, so they pull back.

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You can't see this
expansion of the *carabiner

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on low forces, but you can on big ones.

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And so it turns out that this carabiner

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has to accelerate my weight up

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at the same 9.8 meters per second squared,

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which turns out to be about 600 Newtons.

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Yep, 600 of these need to
hold one skinny guy like me.

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Okay, moving on, this carabiner says

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that it can hold up to 26 kilonewtons.

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Kilonewton is basically
a thousand Newtons.

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So it means that it
could hold about 40 me.

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I wish I would have a clone machine,

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so I could demonstrate this to you.

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Then imagine how many videos
all of these me could create.

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(bright music)

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So if you wanna see us
create more videos like this,

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click the join button, it really helps.

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And I promise I will
spend every single penny

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I get from you guys on
buying a clone machine.

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Enjoy.

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(chuckling) Okay, so you can hang 40 me

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on one single carabiner,
that's pretty impressive.

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Although there are things
that you must know.

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First of all, all of these ratings

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are for new equipment,

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wear and tear does not
go into that rating.

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How bad is that?

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Well, I asked my friend,
Ryan from YouTube channel,

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HowNOTtoHighline because he has a hobby

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of breaking stuff.

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And according to his tests,

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most of the metals tend
to last pretty well.

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Although with soft things,
things are totally different.

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- [Ryan] Black Diamond sling
with a 22 kilonewton MBS.

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(machine whirs)

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(metallic clang)

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What? Was the MBS
on 22 kilonewtons?

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- [Man] Yeah.

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- Yep, a sling rated at 22
kilonewtons broke at six.

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And here is another one.

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- [Ryan] Woo, that's a great condition.

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- [Man] Would not whip.

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- [Ryan] No, not whip.

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I would tie my dog to this though.

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(machine whirs)

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All right.

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- [Man] I wouldn't tie
a very big dog with that.

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- [Ryan] (giggling) All right,
let's see how big of a dog

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could you have tied with this?

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Ooh, a Chihuahua.

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(man chuckles)

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- Yeah, so if you're one of these people

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who like to save money and use very old,

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worn down slings, good luck.

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- [Ryan] 24 kilonewtons,

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(machine whirs)

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that did not stretch that much.

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Oh, guess, guess.

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- [Man] I saw.

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- [Ryan] Four kilonewtons,
what the fuck, man?

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- 4,000 Newtons, okay how
much does such sling can hold?

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Well, that's pretty easy.

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Just divide 4,000 Newtons by 9.8.

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Or if you want easier, by 10
and you get 400 kilograms.

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That sounds quite a lot. 
No? 400 kilograms?

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Well, all of these conversions
from force to kilograms

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that I have been talking so far

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are based on the fact that the
weight is hanging statically.

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Once the thing starts
falling, everything changes.

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- [Man] Go.

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(metallic clanking)

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- So what you have just
seen is a clip from DMM,

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where they dropped 80 kilograms of mass,

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and that broke a brand new Dyneema sling.

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Now my goal is not to scare
you, it's the opposite.

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I want to bring the
awareness that climbing gear

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is not magic, and if you use
it incorrectly, it might fail.

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Fun fact, do you know
this joke that climbers

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like to say when they
fail on their climbs?

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That today is a high gravity day.

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Well, turns out that's true,

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gravity does change from month to month.

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So if you are one of those people

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who like to complain that
today is a bad humidity,

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or bad temperature, now you
have a right to complain

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that today's a bad gravity day, yay!

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Okay, let's see what happens

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when objects like us,
climbers, start falling.

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That was a 10 meters fall.

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Let's see how much force such fall

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would generate to the climber.

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The formula for that would be similar

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to what we had before, except
that we need to multiply

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this by the distance
the climber was falling,

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and divide by the distance
the climber was slowing down.

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And did you actually notice

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how soft the fall for the climber was?

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So imagine driving a car in a highway,

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and pressing on the brake
gently while you come to a stop.

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No problems right?

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Now imagine you are not driving so fast,

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you're in a city, you're driving slowly,

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but you slam on the brake,

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that would not feel very nice, right?

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So here is the first thing
I want you to remember

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out of this video, the
impact to the climber

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will always be multiplied by the distance

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the climber was falling,
divided by the distance

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of the slow down phase.

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So let's calculate, their falling distance

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was about four quickdraws,

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and their slowdown distance was about

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two and a half quickdraws.

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And we get about 860 Newtons.

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Or if we would replace her with a standard

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80 kilogram climber, that
would be about 1.3 kilonewtons,

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which is not much.

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Although this formula 
has a little problem

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because it will always give you
the value of it just slightly lower

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than it would be in real life.

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But showing you how to
calculate more precisely

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would mean that most of you would probably

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just leave this video right here.

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But we don't need to do that,

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because we can rely on real
life experimental data.

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And who is the boss at
providing such data for us?

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- Hi, I'm Ryan Jenks and-

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- And then that's enough
advertisement for you.

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What they did in this video,

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they put a device measuring
the force on the climber,

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and made a series of falls.

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- (laughing) Zach.

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00:11:07,410 --> 00:11:09,143
For science, woo hoo.

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00:11:12,978 --> 00:11:14,728
That puts me at 1.87.

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00:11:15,950 --> 00:11:18,190
- So most of the falls,
that in my opinion,

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would be a good belaying example,

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00:11:20,340 --> 00:11:22,710
were below two kilonewtons.

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00:11:22,710 --> 00:11:26,430
Now let's take a look at
these two extreme examples.

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00:11:26,430 --> 00:11:29,560
Climber on the left is
five meters above the bolt,

212
00:11:29,560 --> 00:11:31,950
so that would be 10 meters fall

213
00:11:31,950 --> 00:11:34,030
plus the slack in the system.

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00:11:34,030 --> 00:11:37,090
The belayer probably has
about one meter of slack.

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00:11:37,090 --> 00:11:40,150
And then there is probably
one more meter of slack

216
00:11:40,150 --> 00:11:41,590
in between the quickdraws.

217
00:11:41,590 --> 00:11:44,970
So in total, we are
looking at 12 meters fall.

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00:11:44,970 --> 00:11:48,470
While climber on the right is
only one meter above the bolt.

219
00:11:48,470 --> 00:11:51,320
And let's say that
belayer is really afraid,

220
00:11:51,320 --> 00:11:54,660
and he's going to give a very
hard catch for the climber.

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00:11:54,660 --> 00:11:57,183
So we are looking at two meters fall.

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00:11:58,040 --> 00:12:03,040
So a massive 12 meters fall,
or a small two meters fall.

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00:12:03,090 --> 00:12:06,440
Which one do you think
is going to be softer for the climber?

224
00:12:06,440 --> 00:12:08,420
Well, let's see, we know how much

225
00:12:08,420 --> 00:12:11,440
the climbers will fall.
But now we need to find out

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00:12:11,440 --> 00:12:14,880
the slowed down distances
for both of the cases.

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00:12:14,880 --> 00:12:17,700
And that depends mainly on two things.

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00:12:17,700 --> 00:12:20,580
First is the displacement of the belayer.

229
00:12:20,580 --> 00:12:24,090
On a big, big whipper, the
belayer will probably fly

230
00:12:24,090 --> 00:12:27,220
about two meters, while on a small fall,

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00:12:27,220 --> 00:12:30,110
let's assume very common
mistake for beginners,

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where the belayer just takes the slack out

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00:12:32,560 --> 00:12:34,430
and belays very hard.

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00:12:34,430 --> 00:12:38,210
And the second factor is
the stretch of the rope.

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00:12:38,210 --> 00:12:41,430
Rope manufacturers claim
that if you put 80 kilogram

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00:12:41,430 --> 00:12:44,700
mass on a dynamic rope statically,

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00:12:44,700 --> 00:12:49,160
like so, without movement,
the rope will stretch 10%.

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00:12:49,160 --> 00:12:52,600
And dynamic stretch, when
you take a lead fall,

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00:12:52,600 --> 00:12:55,440
is up to 30%.

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00:12:55,440 --> 00:12:58,550
Well up to 30% is not very helpful for us.

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00:12:58,550 --> 00:13:01,590
What we need to know is
the stretch of this rope

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00:13:01,590 --> 00:13:04,530
from two to four kilonewtons force,

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00:13:04,530 --> 00:13:06,810
that's where the lead falls are.

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00:13:06,810 --> 00:13:09,250
And yet again, I was texting Ryan.

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00:13:09,250 --> 00:13:11,280
- So, I'm gonna pull some dynamic rope,

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00:13:11,280 --> 00:13:12,820
to see how much it stretches.

247
00:13:12,820 --> 00:13:14,928
At first, we thought
it's gonna be very easy,

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00:13:14,928 --> 00:13:17,990
just go to the park, stretch
the rope to different forces,

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00:13:17,990 --> 00:13:21,110
and measure the elongation of the rope.

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00:13:21,110 --> 00:13:24,660
Well, sometimes easy is hard.

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00:13:24,660 --> 00:13:27,570
When you stretch the rope to certain force

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00:13:27,570 --> 00:13:30,120
and leave it there, the force will start

253
00:13:30,120 --> 00:13:33,580
dropping on the rope, the
rope kind of just gives up.

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00:13:33,580 --> 00:13:36,890
While this is very interesting,
it's not critical for us.

255
00:13:36,890 --> 00:13:39,500
The only thing he needed
to do is to pull the rope

256
00:13:39,500 --> 00:13:42,390
as fast as he can to desired force,

257
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and measure the stretch.

258
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- [Ryan] Okay, oh my God,
that's the seven mark...

259
00:13:49,610 --> 00:13:55,490
6.9 meters... it stretches...
when you pull it...

260
00:13:55,630 --> 00:13:59,380
a dynamic rope... to four kilonewtons.

261
00:13:59,380 --> 00:14:01,480
But then there is
another interesting factor,

262
00:14:01,480 --> 00:14:04,200
once you load the rope to high forces,

263
00:14:04,200 --> 00:14:06,090
it takes some time for the rope

264
00:14:06,090 --> 00:14:08,590
to get back to its original length.

265
00:14:08,590 --> 00:14:11,490
This is what's known as rope resting,

266
00:14:11,490 --> 00:14:13,810
and it was really cool
to see this in action.

267
00:14:13,810 --> 00:14:16,913
- [Ryan] See the Grigri
getting pulled back slowly?

268
00:14:19,540 --> 00:14:22,838
Super interesting, probably
way more interesting

269
00:14:22,838 --> 00:14:25,260
to me than it is to you right now.

270
00:14:25,260 --> 00:14:27,860
So after he spent like
four hours in the park

271
00:14:27,860 --> 00:14:31,460
pulling the ropes, the
results were that on forces

272
00:14:31,460 --> 00:14:33,890
from two to four kilonewtons,

273
00:14:33,890 --> 00:14:37,750
the rope stretched to about 20%.

274
00:14:37,750 --> 00:14:41,180
Great, so let's use that
in our calculations.

275
00:14:41,180 --> 00:14:45,240
On a big fall, we have 27
meters of rope in total,

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00:14:45,240 --> 00:14:49,570
so that would be 5.4 meters of stretch.

277
00:14:49,570 --> 00:14:52,600
While in a small fall, we
have five meters of rope,

278
00:14:52,600 --> 00:14:54,940
and that would be one meter of stretch.

279
00:14:54,940 --> 00:14:58,600
However, our belayer is
panicking and taking hard,

280
00:14:58,600 --> 00:15:02,170
so he will take half of
that stretch for himself,

281
00:15:02,170 --> 00:15:06,540
leaving only half a meter
of stretch for the climber.

282
00:15:06,540 --> 00:15:09,660
And ta-da, the big, big whipper

283
00:15:09,660 --> 00:15:13,580
will be two and a half
times softer for the climber

284
00:15:13,580 --> 00:15:15,113
than the small fall.

285
00:15:16,470 --> 00:15:17,870
Oh, I love fun facts,

286
00:15:17,870 --> 00:15:19,180
here is another one.

287
00:15:19,180 --> 00:15:21,830
Imagine that you were climbing and failed,

288
00:15:21,830 --> 00:15:25,370
but humidity was good,
temperature was good,

289
00:15:25,370 --> 00:15:27,483
even the gravity was good that day.

290
00:15:28,370 --> 00:15:30,030
You can still blame the moon.

291
00:15:30,030 --> 00:15:33,330
- [Narrator] Negligibly but truly,

292
00:15:33,330 --> 00:15:36,460
you weigh about a million
of your weight less

293
00:15:36,460 --> 00:15:38,740
when the moon is directly above you.

294
00:15:38,740 --> 00:15:41,360
- So if you wanna ascend,
climb when the moon

295
00:15:41,360 --> 00:15:45,520
is directly above you, you're welcome.

296
00:15:45,520 --> 00:15:48,360
I remember I was projecting
this really long route

297
00:15:48,360 --> 00:15:52,010
of 35 meters, and the first
time I managed to link

298
00:15:52,010 --> 00:15:54,707
all the cruxes and arrive at the anchor.

299
00:15:54,707 --> 00:15:57,300
At the moment when 
I was pulling the rope up

300
00:15:57,300 --> 00:15:58,650
to clip the anchor,

301
00:15:58,650 --> 00:16:00,810
my belayer couldn't see me very well.

302
00:16:00,810 --> 00:16:03,300
So he just gave me a lot of slack.

303
00:16:03,300 --> 00:16:06,930
And on top of that, the
bolt before the anchor

304
00:16:06,930 --> 00:16:10,230
was really far, really ran out.

305
00:16:10,230 --> 00:16:12,800
So while I was dragging the rope up,

306
00:16:12,800 --> 00:16:15,720
I lost my balance and took a fall.

307
00:16:15,720 --> 00:16:17,510
The wall is flying in front of me,

308
00:16:17,510 --> 00:16:20,140
and I'm thinking, "Why I'm still falling?

309
00:16:20,140 --> 00:16:21,930
Hmm, this is unusual."

310
00:16:21,930 --> 00:16:23,470
Then I stopped and looked up,

311
00:16:23,470 --> 00:16:25,970
it was maybe five or
six quickdraws above me,

312
00:16:25,970 --> 00:16:29,390
probably about 15 meters of fall.

313
00:16:29,390 --> 00:16:34,320
But the fall was super soft,
it's like riding an elevator.

314
00:16:34,320 --> 00:16:36,860
So here is another
takeaway out of this video,

315
00:16:36,860 --> 00:16:39,130
if the climber is really high up,

316
00:16:39,130 --> 00:16:41,700
he has a lot of rope to absorb the fall.

317
00:16:41,700 --> 00:16:44,930
So as long as he doesn't
fall onto something,

318
00:16:44,930 --> 00:16:49,220
the fall will be soft, no
matter how you belay that.

319
00:16:49,220 --> 00:16:51,960
However, if the climber is not so high,

320
00:16:51,960 --> 00:16:54,790
he doesn't have so much
rope to absorb the fall,

321
00:16:54,790 --> 00:16:59,680
then soft dynamic belaying
is really important.

322
00:16:59,680 --> 00:17:02,050
And you can ask any light climber,

323
00:17:02,050 --> 00:17:05,620
how many times they
had their ankles broken

324
00:17:05,620 --> 00:17:07,550
due to hard catches.

325
00:17:07,550 --> 00:17:09,300
Okay, let's switch gears a little bit.

326
00:17:09,300 --> 00:17:11,300
Let's talk about friction,

327
00:17:11,300 --> 00:17:13,710
'cause the more friction you have,

328
00:17:13,710 --> 00:17:17,000
the harder the fall for
the climber will be.

329
00:17:17,000 --> 00:17:19,540
And here is a very
extreme example of that.

330
00:17:19,540 --> 00:17:23,730
- As you can see right
here, we Z dragged it.

331
00:17:23,730 --> 00:17:27,560
And so we're gonna have a
lot of friction when I fall.

332
00:17:27,560 --> 00:17:29,241
And whoo, for science.

333
00:17:29,241 --> 00:17:30,541
Do it!

334
00:17:30,541 --> 00:17:31,374
Oh my God!

335
00:17:34,280 --> 00:17:36,330
- So when you have a lot of friction,

336
00:17:36,330 --> 00:17:39,740
the rope close to the
climber stretches normally,

337
00:17:39,740 --> 00:17:43,960
but the rope closer to belayer
doesn't stretch that much.

338
00:17:43,960 --> 00:17:46,770
It's like having shorter
rope and heavier belayer

339
00:17:46,770 --> 00:17:47,820
at the same time.

340
00:17:47,820 --> 00:17:50,230
And although the force to the harness

341
00:17:50,230 --> 00:17:52,500
was only two and a half kilonewtons,

342
00:17:52,500 --> 00:17:55,918
a lot of the force went
pendulum into the wall.

343
00:17:55,918 --> 00:17:57,330
- Do it.

344
00:17:57,330 --> 00:17:59,530
- And that's how we break ankles.

345
00:17:59,530 --> 00:18:03,410
So extending the Quickdraws
not only helps you to clip

346
00:18:03,410 --> 00:18:05,286
and avoid situations like this,

347
00:18:05,286 --> 00:18:06,119
(upbeat music)

348
00:18:06,119 --> 00:18:09,119
(climber straining)

349
00:18:16,650 --> 00:18:20,650
But also reduces the impact
forces for the climbers.

350
00:18:20,650 --> 00:18:23,930
Okay, let's circle back to the DMM test,

351
00:18:23,930 --> 00:18:25,720
breaking the sling.

352
00:18:25,720 --> 00:18:29,730
Dyneema slings are very static,
they don't stretch at all.

353
00:18:29,730 --> 00:18:31,520
And I hope that by now you understand

354
00:18:31,520 --> 00:18:34,980
that this sudden stop
can create huge forces.

355
00:18:34,980 --> 00:18:37,600
If not, ask somebody to slap you.

356
00:18:37,600 --> 00:18:40,650
This stop on the face will be basically

357
00:18:40,650 --> 00:18:41,950
what you need to understand.

358
00:18:41,950 --> 00:18:43,860
So let's make a very wild

359
00:18:43,860 --> 00:18:46,230
and probably very inaccurate guess

360
00:18:46,230 --> 00:18:51,160
that this sling would stretch
to about five centimeters.

361
00:18:51,160 --> 00:18:54,590
So if we drop 80 kilograms of mass,

362
00:18:54,590 --> 00:18:57,980
the distance of 120 centimeters,

363
00:18:57,980 --> 00:19:01,960
and the absorption distance
is only five centimeters,

364
00:19:01,960 --> 00:19:06,160
we are looking at 19 kilonewtons.

365
00:19:06,160 --> 00:19:08,850
If that is not gonna break the sling,

366
00:19:08,850 --> 00:19:11,990
it's definitely gonna break you.

367
00:19:11,990 --> 00:19:14,070
Woo, if you're still watching,

368
00:19:14,070 --> 00:19:16,030
that probably means that you should be

369
00:19:16,030 --> 00:19:18,440
at least a little bit geeky.

370
00:19:18,440 --> 00:19:20,443
So here is a dessert for you.

371
00:19:21,320 --> 00:19:23,840
There is no gravity.

372
00:19:23,840 --> 00:19:27,120
Yeah, objects don't attract each other,

373
00:19:27,120 --> 00:19:28,880
there is only space time.

374
00:19:28,880 --> 00:19:31,800
- You feel as though you're
being pushed into the ground,

375
00:19:31,800 --> 00:19:34,110
not because of a force called gravity,

376
00:19:34,110 --> 00:19:36,360
but because time is moving faster

377
00:19:36,360 --> 00:19:38,890
for your head than for your feet.

378
00:19:38,890 --> 00:19:41,440
- This and all the other
resources that I use

379
00:19:41,440 --> 00:19:44,590
to create this video will
be in the description.

380
00:19:44,590 --> 00:19:47,280
And now please go send some love to Ryan

381
00:19:47,280 --> 00:19:50,460
for providing me with all
of his experimental data

382
00:19:50,460 --> 00:19:52,360
that I used in this video.

383
00:19:52,360 --> 00:19:55,460
So don't forget to subscribe
and support our channels

384
00:19:55,460 --> 00:19:57,960
if you wanna see more content like this.

385
00:19:57,960 --> 00:19:58,793
Enjoy.