- It says kilonewtons...
And after this video,
you will have a much better understanding
than probably 99% of the rest of the climbers,
what these kilonewtons actually mean,
and what forces are involved in real climbing falls.
And then I will explain why big, big whippers
are often much softer than small falls.
But first, let's find out what is force.
I like to play with my Instagram followers,
so I decided to ask them what comes to their mind
when they hear the word force.
Half of the people said
that it has something to do with "Star Wars".
Fair enough.
And then before you start thinking
that half of my Instagram followers are really smart,
I have to say that majority of them didn't vote it at all.
So I imagine something like...
What is force?
(lively music) (electronic buzzing)
Okay, but those who wanted to sound smart
said that force is mass times acceleration,
which is the formula that Newton, this guy,
came up with.
- [Newton] Ooh yah.
And that's why we measure force in Newtons.
Which to me is a little bit funny when you think about it,
imagine Newton.
(gentle music)
So we measure mass in kilograms,
and we measure acceleration in meters per second squared.
Then we should measure force in Newtons.
(clapping)
So to put this formula into perspective,
it's like one Newton, this guy,
is pushing one kilogram of mass
and that makes that mass to accelerate
by one meter per second, every second.
So here I have a carabiner.
If I put all my weight on it, like so,
the question is, what's the force right now
into this carabiner?
So if we look back to the formula,
we can say that mass is my mass
multiplied by acceleration.
What acceleration? I'm hanging on a tree.
There is no movement, no acceleration...
or is there an acceleration?
(upbeat music)
Look, so you've probably seen this experiment before,
I have heavy object and a light object.
And the question is, if I let go
both of them at the same time,
which one is gonna hit the ground first?
Let's try.
So yes, they fell at the same time,
because that's what gravity does,
it makes objects fall at exactly the same acceleration
of 9.8 meters per second per second.
So then I'm hanging on this carabiner,
gravity is pulling me down.
But in order for me to not move down,
there must be opposite force, which would be pulling me up.
Here I have a spring.
While the gravity is pulling the rock down,
the spring is pulling the rock up.
So the carabiner is actually like a very, very stiff spring,
which is pulling me up.
The molecules of the carabiner when I'm hanging on it
are being spread apart,
but they like to stay together, so they pull back.
You can't see this expansion of the *carabiner
on low forces, but you can on big ones.
And so it turns out that this carabiner
has to accelerate my weight up
at the same 9.8 meters per second squared,
which turns out to be about 600 Newtons.
Yep, 600 of these need to hold one skinny guy like me.
Okay, moving on, this carabiner says
that it can hold up to 26 kilonewtons.
Kilonewton is basically a thousand Newtons.
So it means that it could hold about 40 me.
I wish I would have a clone machine,
so I could demonstrate this to you.
Then imagine how many videos all of these me could create.
(bright music)
So if you wanna see us create more videos like this,
click the join button, it really helps.
And I promise I will spend every single penny
I get from you guys on buying a clone machine.
Enjoy.
(chuckling) Okay, so you can hang 40 me
on one single carabiner, that's pretty impressive.
Although there are things that you must know.
First of all, all of these ratings
are for new equipment,
wear and tear does not go into that rating.
How bad is that?
Well, I asked my friend, Ryan from YouTube channel,
HowNOTtoHighline because he has a hobby
of breaking stuff.
And according to his tests,
most of the metals tend to last pretty well.
Although with soft things, things are totally different.
- [Ryan] Black Diamond sling with a 22 kilonewton MBS.
(machine whirs)
(metallic clang)
What? Was the MBS on 22 kilonewtons?
- [Man] Yeah.
- Yep, a sling rated at 22 kilonewtons broke at six.
And here is another one.
- [Ryan] Woo, that's a great condition.
- [Man] Would not whip.
- [Ryan] No, not whip.
I would tie my dog to this though.
(machine whirs)
All right.
- [Man] I wouldn't tie a very big dog with that.
- [Ryan] (giggling) All right, let's see how big of a dog
could you have tied with this?
Ooh, a Chihuahua.
(man chuckles)
- Yeah, so if you're one of these people
who like to save money and use very old,
worn down slings, good luck.
- [Ryan] 24 kilonewtons,
(machine whirs)
that did not stretch that much.
Oh, guess, guess.
- [Man] I saw.
- [Ryan] Four kilonewtons, what the fuck, man?
- 4,000 Newtons, okay how much does such sling can hold?
Well, that's pretty easy.
Just divide 4,000 Newtons by 9.8.
Or if you want easier, by 10 and you get 400 kilograms.
That sounds quite a lot. No? 400 kilograms?
Well, all of these conversions from force to kilograms
that I have been talking so far
are based on the fact that the weight is hanging statically.
Once the thing starts falling, everything changes.
- [Man] Go.
(metallic clanking)
- So what you have just seen is a clip from DMM,
where they dropped 80 kilograms of mass,
and that broke a brand new Dyneema sling.
Now my goal is not to scare you, it's the opposite.
I want to bring the awareness that climbing gear
is not magic, and if you use it incorrectly, it might fail.
Fun fact, do you know this joke that climbers
like to say when they fail on their climbs?
That today is a high gravity day.
Well, turns out that's true,
gravity does change from month to month.
So if you are one of those people
who like to complain that today is a bad humidity,
or bad temperature, now you have a right to complain
that today's a bad gravity day, yay!
Okay, let's see what happens
when objects like us, climbers, start falling.
That was a 10 meters fall.
Let's see how much force such fall
would generate to the climber.
The formula for that would be similar
to what we had before, except that we need to multiply
this by the distance the climber was falling,
and divide by the distance the climber was slowing down.
And did you actually notice
how soft the fall for the climber was?
So imagine driving a car in a highway,
and pressing on the brake gently while you come to a stop.
No problems right?
Now imagine you are not driving so fast,
you're in a city, you're driving slowly,
but you slam on the brake,
that would not feel very nice, right?
So here is the first thing I want you to remember
out of this video, the impact to the climber
will always be multiplied by the distance
the climber was falling, divided by the distance
of the slow down phase.
So let's calculate, their falling distance
was about four quickdraws,
and their slowdown distance was about
two and a half quickdraws.
And we get about 860 Newtons.
Or if we would replace her with a standard
80 kilogram climber, that would be about 1.3 kilonewtons,
which is not much.
Although this formula has a little problem
because it will always give you the value of it just slightly lower
than it would be in real life.
But showing you how to calculate more precisely
would mean that most of you would probably
just leave this video right here.
But we don't need to do that,
because we can rely on real life experimental data.
And who is the boss at providing such data for us?
- Hi, I'm Ryan Jenks and-
- And then that's enough advertisement for you.
What they did in this video,
they put a device measuring the force on the climber,
and made a series of falls.
- (laughing) Zach.
For science, woo hoo.
That puts me at 1.87.
- So most of the falls, that in my opinion,
would be a good belaying example,
were below two kilonewtons.
Now let's take a look at these two extreme examples.
Climber on the left is five meters above the bolt,
so that would be 10 meters fall
plus the slack in the system.
The belayer probably has about one meter of slack.
And then there is probably one more meter of slack
in between the quickdraws.
So in total, we are looking at 12 meters fall.
While climber on the right is only one meter above the bolt.
And let's say that belayer is really afraid,
and he's going to give a very hard catch for the climber.
So we are looking at two meters fall.
So a massive 12 meters fall, or a small two meters fall.
Which one do you think is going to be softer for the climber?
Well, let's see, we know how much
the climbers will fall. But now we need to find out
the slowed down distances for both of the cases.
And that depends mainly on two things.
First is the displacement of the belayer.
On a big, big whipper, the belayer will probably fly
about two meters, while on a small fall,
let's assume very common mistake for beginners,
where the belayer just takes the slack out
and belays very hard.
And the second factor is the stretch of the rope.
Rope manufacturers claim that if you put 80 kilogram
mass on a dynamic rope statically,
like so, without movement, the rope will stretch 10%.
And dynamic stretch, when you take a lead fall,
is up to 30%.
Well up to 30% is not very helpful for us.
What we need to know is the stretch of this rope
from two to four kilonewtons force,
that's where the lead falls are.
And yet again, I was texting Ryan.
- So, I'm gonna pull some dynamic rope,
to see how much it stretches.
At first, we thought it's gonna be very easy,
just go to the park, stretch the rope to different forces,
and measure the elongation of the rope.
Well, sometimes easy is hard.
When you stretch the rope to certain force
and leave it there, the force will start
dropping on the rope, the rope kind of just gives up.
While this is very interesting, it's not critical for us.
The only thing he needed to do is to pull the rope
as fast as he can to desired force,
and measure the stretch.
- [Ryan] Okay, oh my God, that's the seven mark...
6.9 meters... it stretches... when you pull it...
a dynamic rope... to four kilonewtons.
But then there is another interesting factor,
once you load the rope to high forces,
it takes some time for the rope
to get back to its original length.
This is what's known as rope resting,
and it was really cool to see this in action.
- [Ryan] See the Grigri getting pulled back slowly?
Super interesting, probably way more interesting
to me than it is to you right now.
So after he spent like four hours in the park
pulling the ropes, the results were that on forces
from two to four kilonewtons,
the rope stretched to about 20%.
Great, so let's use that in our calculations.
On a big fall, we have 27 meters of rope in total,
so that would be 5.4 meters of stretch.
While in a small fall, we have five meters of rope,
and that would be one meter of stretch.
However, our belayer is panicking and taking hard,
so he will take half of that stretch for himself,
leaving only half a meter of stretch for the climber.
And ta-da, the big, big whipper
will be two and a half times softer for the climber
than the small fall.
Oh, I love fun facts,
here is another one.
Imagine that you were climbing and failed,
but humidity was good, temperature was good,
even the gravity was good that day.
You can still blame the moon.
- [Narrator] Negligibly but truly,
you weigh about a million of your weight less
when the moon is directly above you.
- So if you wanna ascend, climb when the moon
is directly above you, you're welcome.
I remember I was projecting this really long route
of 35 meters, and the first time I managed to link
all the cruxes and arrive at the anchor.
At the moment when I was pulling the rope up
to clip the anchor,
my belayer couldn't see me very well.
So he just gave me a lot of slack.
And on top of that, the bolt before the anchor
was really far, really ran out.
So while I was dragging the rope up,
I lost my balance and took a fall.
The wall is flying in front of me,
and I'm thinking, "Why I'm still falling?
Hmm, this is unusual."
Then I stopped and looked up,
it was maybe five or six quickdraws above me,
probably about 15 meters of fall.
But the fall was super soft, it's like riding an elevator.
So here is another takeaway out of this video,
if the climber is really high up,
he has a lot of rope to absorb the fall.
So as long as he doesn't fall onto something,
the fall will be soft, no matter how you belay that.
However, if the climber is not so high,
he doesn't have so much rope to absorb the fall,
then soft dynamic belaying is really important.
And you can ask any light climber,
how many times they had their ankles broken
due to hard catches.
Okay, let's switch gears a little bit.
Let's talk about friction,
'cause the more friction you have,
the harder the fall for the climber will be.
And here is a very extreme example of that.
- As you can see right here, we Z dragged it.
And so we're gonna have a lot of friction when I fall.
And whoo, for science.
Do it!
Oh my God!
- So when you have a lot of friction,
the rope close to the climber stretches normally,
but the rope closer to belayer doesn't stretch that much.
It's like having shorter rope and heavier belayer
at the same time.
And although the force to the harness
was only two and a half kilonewtons,
a lot of the force went pendulum into the wall.
- Do it.
- And that's how we break ankles.
So extending the Quickdraws not only helps you to clip
and avoid situations like this,
(upbeat music)
(climber straining)
But also reduces the impact forces for the climbers.
Okay, let's circle back to the DMM test,
breaking the sling.
Dyneema slings are very static, they don't stretch at all.
And I hope that by now you understand
that this sudden stop can create huge forces.
If not, ask somebody to slap you.
This stop on the face will be basically
what you need to understand.
So let's make a very wild
and probably very inaccurate guess
that this sling would stretch to about five centimeters.
So if we drop 80 kilograms of mass,
the distance of 120 centimeters,
and the absorption distance is only five centimeters,
we are looking at 19 kilonewtons.
If that is not gonna break the sling,
it's definitely gonna break you.
Woo, if you're still watching,
that probably means that you should be
at least a little bit geeky.
So here is a dessert for you.
There is no gravity.
Yeah, objects don't attract each other,
there is only space time.
- You feel as though you're being pushed into the ground,
not because of a force called gravity,
but because time is moving faster
for your head than for your feet.
- This and all the other resources that I use
to create this video will be in the description.
And now please go send some love to Ryan
for providing me with all of his experimental data
that I used in this video.
So don't forget to subscribe and support our channels
if you wanna see more content like this.
Enjoy.