WEBVTT 00:00:01.610 --> 00:00:03.943 - It says kilonewtons... 00:00:04.830 --> 00:00:06.700 And after this video, 00:00:06.700 --> 00:00:09.240 you will have a much better understanding 00:00:09.240 --> 00:00:12.940 than probably 99% of the rest of the climbers, 00:00:12.940 --> 00:00:16.010 what these kilonewtons actually mean, 00:00:16.010 --> 00:00:20.420 and what forces are involved in real climbing falls. 00:00:20.420 --> 00:00:23.710 And then I will explain why big, big whippers 00:00:23.710 --> 00:00:27.140 are often much softer than small falls. 00:00:27.140 --> 00:00:30.280 But first, let's find out what is force. 00:00:30.280 --> 00:00:32.610 I like to play with my Instagram followers, 00:00:32.610 --> 00:00:36.310 so I decided to ask them what comes to their mind 00:00:36.310 --> 00:00:38.710 when they hear the word force. 00:00:38.710 --> 00:00:40.040 Half of the people said 00:00:40.040 --> 00:00:43.440 that it has something to do with "Star Wars". 00:00:43.440 --> 00:00:44.590 Fair enough. 00:00:44.590 --> 00:00:46.480 And then before you start thinking 00:00:46.480 --> 00:00:50.640 that half of my Instagram followers are really smart, 00:00:50.640 --> 00:00:53.870 I have to say that majority of them didn't vote it at all. 00:00:53.870 --> 00:00:55.413 So I imagine something like... 00:00:55.413 --> 00:00:57.883 What is force? 00:00:57.883 --> 00:01:00.600 (lively music) (electronic buzzing) 00:01:00.600 --> 00:01:03.060 Okay, but those who wanted to sound smart 00:01:03.060 --> 00:01:07.150 said that force is mass times acceleration, 00:01:07.150 --> 00:01:09.860 which is the formula that Newton, this guy, 00:01:09.860 --> 00:01:10.917 came up with. 00:01:10.917 --> 00:01:11.820 - [Newton] Ooh yah. 00:01:11.820 --> 00:01:14.400 And that's why we measure force in Newtons. 00:01:14.400 --> 00:01:17.210 Which to me is a little bit funny when you think about it, 00:01:17.210 --> 00:01:18.550 imagine Newton. 00:01:18.550 --> 00:01:21.133 (gentle music) 00:01:22.230 --> 00:01:24.987 So we measure mass in kilograms, 00:01:27.555 --> 00:01:32.555 and we measure acceleration in meters per second squared. 00:01:35.480 --> 00:01:40.057 Then we should measure force in Newtons. 00:01:40.057 --> 00:01:42.965 (clapping) 00:01:42.965 --> 00:01:45.427 So to put this formula into perspective, 00:01:45.427 --> 00:01:48.990 it's like one Newton, this guy, 00:01:48.990 --> 00:01:52.250 is pushing one kilogram of mass 00:01:52.250 --> 00:01:55.330 and that makes that mass to accelerate 00:01:55.330 --> 00:01:58.870 by one meter per second, every second. 00:01:58.870 --> 00:02:01.560 So here I have a carabiner. 00:02:01.560 --> 00:02:06.470 If I put all my weight on it, like so, 00:02:06.470 --> 00:02:08.840 the question is, what's the force right now 00:02:08.840 --> 00:02:10.110 into this carabiner? 00:02:10.110 --> 00:02:12.470 So if we look back to the formula, 00:02:12.470 --> 00:02:15.920 we can say that mass is my mass 00:02:15.920 --> 00:02:18.543 multiplied by acceleration. 00:02:19.350 --> 00:02:21.300 What acceleration? I'm hanging on a tree. 00:02:21.300 --> 00:02:24.040 There is no movement, no acceleration... 00:02:24.945 --> 00:02:28.175 or is there an acceleration? 00:02:28.175 --> 00:02:29.882 (upbeat music) 00:02:29.882 --> 00:02:33.790 Look, so you've probably seen this experiment before, 00:02:33.790 --> 00:02:37.500 I have heavy object and a light object. 00:02:37.500 --> 00:02:39.410 And the question is, if I let go 00:02:39.410 --> 00:02:41.640 both of them at the same time, 00:02:41.640 --> 00:02:43.943 which one is gonna hit the ground first? 00:02:45.220 --> 00:02:46.053 Let's try. 00:02:55.910 --> 00:02:58.560 So yes, they fell at the same time, 00:02:58.560 --> 00:03:00.270 because that's what gravity does, 00:03:00.270 --> 00:03:04.370 it makes objects fall at exactly the same acceleration 00:03:04.370 --> 00:03:08.803 of 9.8 meters per second per second. 00:03:15.790 --> 00:03:18.510 So then I'm hanging on this carabiner, 00:03:18.510 --> 00:03:20.390 gravity is pulling me down. 00:03:20.390 --> 00:03:23.290 But in order for me to not move down, 00:03:23.290 --> 00:03:27.270 there must be opposite force, which would be pulling me up. 00:03:27.270 --> 00:03:29.490 Here I have a spring. 00:03:29.490 --> 00:03:32.670 While the gravity is pulling the rock down, 00:03:32.670 --> 00:03:35.370 the spring is pulling the rock up. 00:03:35.370 --> 00:03:39.230 So the carabiner is actually like a very, very stiff spring, 00:03:39.230 --> 00:03:41.150 which is pulling me up. 00:03:41.150 --> 00:03:44.270 The molecules of the carabiner when I'm hanging on it 00:03:44.270 --> 00:03:46.050 are being spread apart, 00:03:46.050 --> 00:03:49.850 but they like to stay together, so they pull back. 00:03:49.850 --> 00:03:52.520 You can't see this expansion of the *carabiner 00:03:52.520 --> 00:03:56.123 on low forces, but you can on big ones. 00:04:02.210 --> 00:04:04.870 And so it turns out that this carabiner 00:04:04.870 --> 00:04:08.080 has to accelerate my weight up 00:04:08.080 --> 00:04:12.680 at the same 9.8 meters per second squared, 00:04:12.680 --> 00:04:16.290 which turns out to be about 600 Newtons. 00:04:16.290 --> 00:04:21.290 Yep, 600 of these need to hold one skinny guy like me. 00:04:28.800 --> 00:04:32.210 Okay, moving on, this carabiner says 00:04:32.210 --> 00:04:37.210 that it can hold up to 26 kilonewtons. 00:04:37.567 --> 00:04:41.000 Kilonewton is basically a thousand Newtons. 00:04:41.000 --> 00:04:45.483 So it means that it could hold about 40 me. 00:04:46.650 --> 00:04:48.610 I wish I would have a clone machine, 00:04:48.610 --> 00:04:50.763 so I could demonstrate this to you. 00:04:52.520 --> 00:04:57.520 Then imagine how many videos all of these me could create. 00:04:57.958 --> 00:05:01.040 (bright music) 00:05:01.040 --> 00:05:05.870 So if you wanna see us create more videos like this, 00:05:05.870 --> 00:05:09.150 click the join button, it really helps. 00:05:09.150 --> 00:05:12.050 And I promise I will spend every single penny 00:05:12.050 --> 00:05:15.699 I get from you guys on buying a clone machine. 00:05:15.699 --> 00:05:17.349 Enjoy. 00:05:17.349 --> 00:05:22.180 (chuckling) Okay, so you can hang 40 me 00:05:22.180 --> 00:05:26.570 on one single carabiner, that's pretty impressive. 00:05:26.570 --> 00:05:29.520 Although there are things that you must know. 00:05:29.520 --> 00:05:31.950 First of all, all of these ratings 00:05:31.950 --> 00:05:33.980 are for new equipment, 00:05:33.980 --> 00:05:37.510 wear and tear does not go into that rating. 00:05:37.510 --> 00:05:39.190 How bad is that? 00:05:39.190 --> 00:05:42.686 Well, I asked my friend, Ryan from YouTube channel, 00:05:42.686 --> 00:05:45.770 HowNOTtoHighline because he has a hobby 00:05:45.770 --> 00:05:47.870 of breaking stuff. 00:05:47.870 --> 00:05:50.200 And according to his tests, 00:05:50.200 --> 00:05:53.490 most of the metals tend to last pretty well. 00:05:53.490 --> 00:05:58.490 Although with soft things, things are totally different. 00:05:58.740 --> 00:06:02.033 - [Ryan] Black Diamond sling with a 22 kilonewton MBS. 00:06:03.089 --> 00:06:04.313 (machine whirs) 00:06:04.313 --> 00:06:07.063 (metallic clang) 00:06:09.071 --> 00:06:12.770 What? Was the MBS on 22 kilonewtons? 00:06:12.770 --> 00:06:13.603 - [Man] Yeah. 00:06:13.603 --> 00:06:18.300 - Yep, a sling rated at 22 kilonewtons broke at six. 00:06:19.490 --> 00:06:20.670 And here is another one. 00:06:20.670 --> 00:06:24.970 - [Ryan] Woo, that's a great condition. 00:06:24.970 --> 00:06:26.193 - [Man] Would not whip. 00:06:27.580 --> 00:06:28.723 - [Ryan] No, not whip. 00:06:30.270 --> 00:06:32.000 I would tie my dog to this though. 00:06:32.000 --> 00:06:34.667 (machine whirs) 00:06:36.912 --> 00:06:38.042 All right. 00:06:38.042 --> 00:06:40.417 - [Man] I wouldn't tie a very big dog with that. 00:06:40.417 --> 00:06:44.640 - [Ryan] (giggling) All right, let's see how big of a dog 00:06:44.640 --> 00:06:47.470 could you have tied with this? 00:06:47.470 --> 00:06:49.740 Ooh, a Chihuahua. 00:06:49.740 --> 00:06:50.690 (man chuckles) 00:06:50.690 --> 00:06:53.250 - Yeah, so if you're one of these people 00:06:53.250 --> 00:06:56.330 who like to save money and use very old, 00:06:56.330 --> 00:06:58.780 worn down slings, good luck. 00:06:58.780 --> 00:07:00.345 - [Ryan] 24 kilonewtons, 00:07:00.345 --> 00:07:03.012 (machine whirs) 00:07:04.067 --> 00:07:05.580 that did not stretch that much. 00:07:05.580 --> 00:07:08.286 Oh, guess, guess. 00:07:08.286 --> 00:07:09.119 - [Man] I saw. 00:07:09.119 --> 00:07:13.440 - [Ryan] Four kilonewtons, what the fuck, man? 00:07:13.440 --> 00:07:18.440 - 4,000 Newtons, okay how much does such sling can hold? 00:07:19.420 --> 00:07:20.660 Well, that's pretty easy. 00:07:20.660 --> 00:07:24.700 Just divide 4,000 Newtons by 9.8. 00:07:24.700 --> 00:07:29.700 Or if you want easier, by 10 and you get 400 kilograms. 00:07:29.870 --> 00:07:32.763 That sounds quite a lot. No? 400 kilograms? 00:07:33.940 --> 00:07:38.940 Well, all of these conversions from force to kilograms 00:07:38.950 --> 00:07:41.270 that I have been talking so far 00:07:41.270 --> 00:07:45.690 are based on the fact that the weight is hanging statically. 00:07:45.690 --> 00:07:49.541 Once the thing starts falling, everything changes. 00:07:49.541 --> 00:07:50.425 - [Man] Go. 00:07:50.425 --> 00:07:53.800 (metallic clanking) 00:07:53.800 --> 00:07:56.840 - So what you have just seen is a clip from DMM, 00:07:56.840 --> 00:07:59.900 where they dropped 80 kilograms of mass, 00:07:59.900 --> 00:08:03.510 and that broke a brand new Dyneema sling. 00:08:03.510 --> 00:08:06.590 Now my goal is not to scare you, it's the opposite. 00:08:06.590 --> 00:08:09.520 I want to bring the awareness that climbing gear 00:08:09.520 --> 00:08:14.393 is not magic, and if you use it incorrectly, it might fail. 00:08:16.600 --> 00:08:19.350 Fun fact, do you know this joke that climbers 00:08:19.350 --> 00:08:21.830 like to say when they fail on their climbs? 00:08:21.830 --> 00:08:24.890 That today is a high gravity day. 00:08:24.890 --> 00:08:27.070 Well, turns out that's true, 00:08:27.070 --> 00:08:30.200 gravity does change from month to month. 00:08:30.200 --> 00:08:32.580 So if you are one of those people 00:08:32.580 --> 00:08:35.830 who like to complain that today is a bad humidity, 00:08:35.830 --> 00:08:38.760 or bad temperature, now you have a right to complain 00:08:38.760 --> 00:08:41.690 that today's a bad gravity day, yay! 00:08:41.690 --> 00:08:43.950 Okay, let's see what happens 00:08:43.950 --> 00:08:47.873 when objects like us, climbers, start falling. 00:08:51.100 --> 00:08:54.090 That was a 10 meters fall. 00:08:54.090 --> 00:08:56.070 Let's see how much force such fall 00:08:56.070 --> 00:08:58.010 would generate to the climber. 00:08:58.010 --> 00:09:00.210 The formula for that would be similar 00:09:00.210 --> 00:09:03.540 to what we had before, except that we need to multiply 00:09:03.540 --> 00:09:07.010 this by the distance the climber was falling, 00:09:07.010 --> 00:09:11.123 and divide by the distance the climber was slowing down. 00:09:16.870 --> 00:09:18.340 And did you actually notice 00:09:18.340 --> 00:09:20.933 how soft the fall for the climber was? 00:09:23.200 --> 00:09:26.460 So imagine driving a car in a highway, 00:09:26.460 --> 00:09:31.460 and pressing on the brake gently while you come to a stop. 00:09:31.620 --> 00:09:33.110 No problems right? 00:09:33.110 --> 00:09:35.090 Now imagine you are not driving so fast, 00:09:35.090 --> 00:09:37.650 you're in a city, you're driving slowly, 00:09:37.650 --> 00:09:39.043 but you slam on the brake, 00:09:40.200 --> 00:09:43.370 that would not feel very nice, right? 00:09:43.370 --> 00:09:45.700 So here is the first thing I want you to remember 00:09:45.700 --> 00:09:48.820 out of this video, the impact to the climber 00:09:48.820 --> 00:09:51.660 will always be multiplied by the distance 00:09:51.660 --> 00:09:54.990 the climber was falling, divided by the distance 00:09:54.990 --> 00:09:57.360 of the slow down phase. 00:09:57.360 --> 00:10:00.100 So let's calculate, their falling distance 00:10:00.100 --> 00:10:02.300 was about four quickdraws, 00:10:02.300 --> 00:10:04.573 and their slowdown distance was about 00:10:04.573 --> 00:10:06.630 two and a half quickdraws. 00:10:06.630 --> 00:10:09.480 And we get about 860 Newtons. 00:10:09.480 --> 00:10:12.360 Or if we would replace her with a standard 00:10:12.360 --> 00:10:17.360 80 kilogram climber, that would be about 1.3 kilonewtons, 00:10:18.490 --> 00:10:19.910 which is not much. 00:10:19.910 --> 00:10:22.210 Although this formula has a little problem 00:10:22.210 --> 00:10:26.470 because it will always give you the value of it just slightly lower 00:10:26.470 --> 00:10:28.810 than it would be in real life. 00:10:28.810 --> 00:10:31.718 But showing you how to calculate more precisely 00:10:31.718 --> 00:10:33.970 would mean that most of you would probably 00:10:33.970 --> 00:10:35.950 just leave this video right here. 00:10:35.950 --> 00:10:37.830 But we don't need to do that, 00:10:37.830 --> 00:10:41.630 because we can rely on real life experimental data. 00:10:41.630 --> 00:10:44.810 And who is the boss at providing such data for us? 00:10:44.810 --> 00:10:46.180 - Hi, I'm Ryan Jenks and- 00:10:46.180 --> 00:10:49.260 - And then that's enough advertisement for you. 00:10:49.260 --> 00:10:50.750 What they did in this video, 00:10:50.750 --> 00:10:54.440 they put a device measuring the force on the climber, 00:10:54.440 --> 00:10:56.633 and made a series of falls. 00:10:58.859 --> 00:11:00.743 - (laughing) Zach. 00:11:07.410 --> 00:11:09.143 For science, woo hoo. 00:11:12.978 --> 00:11:14.728 That puts me at 1.87. 00:11:15.950 --> 00:11:18.190 - So most of the falls, that in my opinion, 00:11:18.190 --> 00:11:20.340 would be a good belaying example, 00:11:20.340 --> 00:11:22.710 were below two kilonewtons. 00:11:22.710 --> 00:11:26.430 Now let's take a look at these two extreme examples. 00:11:26.430 --> 00:11:29.560 Climber on the left is five meters above the bolt, 00:11:29.560 --> 00:11:31.950 so that would be 10 meters fall 00:11:31.950 --> 00:11:34.030 plus the slack in the system. 00:11:34.030 --> 00:11:37.090 The belayer probably has about one meter of slack. 00:11:37.090 --> 00:11:40.150 And then there is probably one more meter of slack 00:11:40.150 --> 00:11:41.590 in between the quickdraws. 00:11:41.590 --> 00:11:44.970 So in total, we are looking at 12 meters fall. 00:11:44.970 --> 00:11:48.470 While climber on the right is only one meter above the bolt. 00:11:48.470 --> 00:11:51.320 And let's say that belayer is really afraid, 00:11:51.320 --> 00:11:54.660 and he's going to give a very hard catch for the climber. 00:11:54.660 --> 00:11:57.183 So we are looking at two meters fall. 00:11:58.040 --> 00:12:03.040 So a massive 12 meters fall, or a small two meters fall. 00:12:03.090 --> 00:12:06.440 Which one do you think is going to be softer for the climber? 00:12:06.440 --> 00:12:08.420 Well, let's see, we know how much 00:12:08.420 --> 00:12:11.440 the climbers will fall. But now we need to find out 00:12:11.440 --> 00:12:14.880 the slowed down distances for both of the cases. 00:12:14.880 --> 00:12:17.700 And that depends mainly on two things. 00:12:17.700 --> 00:12:20.580 First is the displacement of the belayer. 00:12:20.580 --> 00:12:24.090 On a big, big whipper, the belayer will probably fly 00:12:24.090 --> 00:12:27.220 about two meters, while on a small fall, 00:12:27.220 --> 00:12:30.110 let's assume very common mistake for beginners, 00:12:30.110 --> 00:12:32.560 where the belayer just takes the slack out 00:12:32.560 --> 00:12:34.430 and belays very hard. 00:12:34.430 --> 00:12:38.210 And the second factor is the stretch of the rope. 00:12:38.210 --> 00:12:41.430 Rope manufacturers claim that if you put 80 kilogram 00:12:41.430 --> 00:12:44.700 mass on a dynamic rope statically, 00:12:44.700 --> 00:12:49.160 like so, without movement, the rope will stretch 10%. 00:12:49.160 --> 00:12:52.600 And dynamic stretch, when you take a lead fall, 00:12:52.600 --> 00:12:55.440 is up to 30%. 00:12:55.440 --> 00:12:58.550 Well up to 30% is not very helpful for us. 00:12:58.550 --> 00:13:01.590 What we need to know is the stretch of this rope 00:13:01.590 --> 00:13:04.530 from two to four kilonewtons force, 00:13:04.530 --> 00:13:06.810 that's where the lead falls are. 00:13:06.810 --> 00:13:09.250 And yet again, I was texting Ryan. 00:13:09.250 --> 00:13:11.280 - So, I'm gonna pull some dynamic rope, 00:13:11.280 --> 00:13:12.820 to see how much it stretches. 00:13:12.820 --> 00:13:14.928 At first, we thought it's gonna be very easy, 00:13:14.928 --> 00:13:17.990 just go to the park, stretch the rope to different forces, 00:13:17.990 --> 00:13:21.110 and measure the elongation of the rope. 00:13:21.110 --> 00:13:24.660 Well, sometimes easy is hard. 00:13:24.660 --> 00:13:27.570 When you stretch the rope to certain force 00:13:27.570 --> 00:13:30.120 and leave it there, the force will start 00:13:30.120 --> 00:13:33.580 dropping on the rope, the rope kind of just gives up. 00:13:33.580 --> 00:13:36.890 While this is very interesting, it's not critical for us. 00:13:36.890 --> 00:13:39.500 The only thing he needed to do is to pull the rope 00:13:39.500 --> 00:13:42.390 as fast as he can to desired force, 00:13:42.390 --> 00:13:44.290 and measure the stretch. 00:13:44.290 --> 00:13:49.290 - [Ryan] Okay, oh my God, that's the seven mark... 00:13:49.610 --> 00:13:55.490 6.9 meters... it stretches... when you pull it... 00:13:55.630 --> 00:13:59.380 a dynamic rope... to four kilonewtons. 00:13:59.380 --> 00:14:01.480 But then there is another interesting factor, 00:14:01.480 --> 00:14:04.200 once you load the rope to high forces, 00:14:04.200 --> 00:14:06.090 it takes some time for the rope 00:14:06.090 --> 00:14:08.590 to get back to its original length. 00:14:08.590 --> 00:14:11.490 This is what's known as rope resting, 00:14:11.490 --> 00:14:13.810 and it was really cool to see this in action. 00:14:13.810 --> 00:14:16.913 - [Ryan] See the Grigri getting pulled back slowly? 00:14:19.540 --> 00:14:22.838 Super interesting, probably way more interesting 00:14:22.838 --> 00:14:25.260 to me than it is to you right now. 00:14:25.260 --> 00:14:27.860 So after he spent like four hours in the park 00:14:27.860 --> 00:14:31.460 pulling the ropes, the results were that on forces 00:14:31.460 --> 00:14:33.890 from two to four kilonewtons, 00:14:33.890 --> 00:14:37.750 the rope stretched to about 20%. 00:14:37.750 --> 00:14:41.180 Great, so let's use that in our calculations. 00:14:41.180 --> 00:14:45.240 On a big fall, we have 27 meters of rope in total, 00:14:45.240 --> 00:14:49.570 so that would be 5.4 meters of stretch. 00:14:49.570 --> 00:14:52.600 While in a small fall, we have five meters of rope, 00:14:52.600 --> 00:14:54.940 and that would be one meter of stretch. 00:14:54.940 --> 00:14:58.600 However, our belayer is panicking and taking hard, 00:14:58.600 --> 00:15:02.170 so he will take half of that stretch for himself, 00:15:02.170 --> 00:15:06.540 leaving only half a meter of stretch for the climber. 00:15:06.540 --> 00:15:09.660 And ta-da, the big, big whipper 00:15:09.660 --> 00:15:13.580 will be two and a half times softer for the climber 00:15:13.580 --> 00:15:15.113 than the small fall. 00:15:16.470 --> 00:15:17.870 Oh, I love fun facts, 00:15:17.870 --> 00:15:19.180 here is another one. 00:15:19.180 --> 00:15:21.830 Imagine that you were climbing and failed, 00:15:21.830 --> 00:15:25.370 but humidity was good, temperature was good, 00:15:25.370 --> 00:15:27.483 even the gravity was good that day. 00:15:28.370 --> 00:15:30.030 You can still blame the moon. 00:15:30.030 --> 00:15:33.330 - [Narrator] Negligibly but truly, 00:15:33.330 --> 00:15:36.460 you weigh about a million of your weight less 00:15:36.460 --> 00:15:38.740 when the moon is directly above you. 00:15:38.740 --> 00:15:41.360 - So if you wanna ascend, climb when the moon 00:15:41.360 --> 00:15:45.520 is directly above you, you're welcome. 00:15:45.520 --> 00:15:48.360 I remember I was projecting this really long route 00:15:48.360 --> 00:15:52.010 of 35 meters, and the first time I managed to link 00:15:52.010 --> 00:15:54.707 all the cruxes and arrive at the anchor. 00:15:54.707 --> 00:15:57.300 At the moment when I was pulling the rope up 00:15:57.300 --> 00:15:58.650 to clip the anchor, 00:15:58.650 --> 00:16:00.810 my belayer couldn't see me very well. 00:16:00.810 --> 00:16:03.300 So he just gave me a lot of slack. 00:16:03.300 --> 00:16:06.930 And on top of that, the bolt before the anchor 00:16:06.930 --> 00:16:10.230 was really far, really ran out. 00:16:10.230 --> 00:16:12.800 So while I was dragging the rope up, 00:16:12.800 --> 00:16:15.720 I lost my balance and took a fall. 00:16:15.720 --> 00:16:17.510 The wall is flying in front of me, 00:16:17.510 --> 00:16:20.140 and I'm thinking, "Why I'm still falling? 00:16:20.140 --> 00:16:21.930 Hmm, this is unusual." 00:16:21.930 --> 00:16:23.470 Then I stopped and looked up, 00:16:23.470 --> 00:16:25.970 it was maybe five or six quickdraws above me, 00:16:25.970 --> 00:16:29.390 probably about 15 meters of fall. 00:16:29.390 --> 00:16:34.320 But the fall was super soft, it's like riding an elevator. 00:16:34.320 --> 00:16:36.860 So here is another takeaway out of this video, 00:16:36.860 --> 00:16:39.130 if the climber is really high up, 00:16:39.130 --> 00:16:41.700 he has a lot of rope to absorb the fall. 00:16:41.700 --> 00:16:44.930 So as long as he doesn't fall onto something, 00:16:44.930 --> 00:16:49.220 the fall will be soft, no matter how you belay that. 00:16:49.220 --> 00:16:51.960 However, if the climber is not so high, 00:16:51.960 --> 00:16:54.790 he doesn't have so much rope to absorb the fall, 00:16:54.790 --> 00:16:59.680 then soft dynamic belaying is really important. 00:16:59.680 --> 00:17:02.050 And you can ask any light climber, 00:17:02.050 --> 00:17:05.620 how many times they had their ankles broken 00:17:05.620 --> 00:17:07.550 due to hard catches. 00:17:07.550 --> 00:17:09.300 Okay, let's switch gears a little bit. 00:17:09.300 --> 00:17:11.300 Let's talk about friction, 00:17:11.300 --> 00:17:13.710 'cause the more friction you have, 00:17:13.710 --> 00:17:17.000 the harder the fall for the climber will be. 00:17:17.000 --> 00:17:19.540 And here is a very extreme example of that. 00:17:19.540 --> 00:17:23.730 - As you can see right here, we Z dragged it. 00:17:23.730 --> 00:17:27.560 And so we're gonna have a lot of friction when I fall. 00:17:27.560 --> 00:17:29.241 And whoo, for science. 00:17:29.241 --> 00:17:30.541 Do it! 00:17:30.541 --> 00:17:31.374 Oh my God! 00:17:34.280 --> 00:17:36.330 - So when you have a lot of friction, 00:17:36.330 --> 00:17:39.740 the rope close to the climber stretches normally, 00:17:39.740 --> 00:17:43.960 but the rope closer to belayer doesn't stretch that much. 00:17:43.960 --> 00:17:46.770 It's like having shorter rope and heavier belayer 00:17:46.770 --> 00:17:47.820 at the same time. 00:17:47.820 --> 00:17:50.230 And although the force to the harness 00:17:50.230 --> 00:17:52.500 was only two and a half kilonewtons, 00:17:52.500 --> 00:17:55.918 a lot of the force went pendulum into the wall. 00:17:55.918 --> 00:17:57.330 - Do it. 00:17:57.330 --> 00:17:59.530 - And that's how we break ankles. 00:17:59.530 --> 00:18:03.410 So extending the Quickdraws not only helps you to clip 00:18:03.410 --> 00:18:05.286 and avoid situations like this, 00:18:05.286 --> 00:18:06.119 (upbeat music) 00:18:06.119 --> 00:18:09.119 (climber straining) 00:18:16.650 --> 00:18:20.650 But also reduces the impact forces for the climbers. 00:18:20.650 --> 00:18:23.930 Okay, let's circle back to the DMM test, 00:18:23.930 --> 00:18:25.720 breaking the sling. 00:18:25.720 --> 00:18:29.730 Dyneema slings are very static, they don't stretch at all. 00:18:29.730 --> 00:18:31.520 And I hope that by now you understand 00:18:31.520 --> 00:18:34.980 that this sudden stop can create huge forces. 00:18:34.980 --> 00:18:37.600 If not, ask somebody to slap you. 00:18:37.600 --> 00:18:40.650 This stop on the face will be basically 00:18:40.650 --> 00:18:41.950 what you need to understand. 00:18:41.950 --> 00:18:43.860 So let's make a very wild 00:18:43.860 --> 00:18:46.230 and probably very inaccurate guess 00:18:46.230 --> 00:18:51.160 that this sling would stretch to about five centimeters. 00:18:51.160 --> 00:18:54.590 So if we drop 80 kilograms of mass, 00:18:54.590 --> 00:18:57.980 the distance of 120 centimeters, 00:18:57.980 --> 00:19:01.960 and the absorption distance is only five centimeters, 00:19:01.960 --> 00:19:06.160 we are looking at 19 kilonewtons. 00:19:06.160 --> 00:19:08.850 If that is not gonna break the sling, 00:19:08.850 --> 00:19:11.990 it's definitely gonna break you. 00:19:11.990 --> 00:19:14.070 Woo, if you're still watching, 00:19:14.070 --> 00:19:16.030 that probably means that you should be 00:19:16.030 --> 00:19:18.440 at least a little bit geeky. 00:19:18.440 --> 00:19:20.443 So here is a dessert for you. 00:19:21.320 --> 00:19:23.840 There is no gravity. 00:19:23.840 --> 00:19:27.120 Yeah, objects don't attract each other, 00:19:27.120 --> 00:19:28.880 there is only space time. 00:19:28.880 --> 00:19:31.800 - You feel as though you're being pushed into the ground, 00:19:31.800 --> 00:19:34.110 not because of a force called gravity, 00:19:34.110 --> 00:19:36.360 but because time is moving faster 00:19:36.360 --> 00:19:38.890 for your head than for your feet. 00:19:38.890 --> 00:19:41.440 - This and all the other resources that I use 00:19:41.440 --> 00:19:44.590 to create this video will be in the description. 00:19:44.590 --> 00:19:47.280 And now please go send some love to Ryan 00:19:47.280 --> 00:19:50.460 for providing me with all of his experimental data 00:19:50.460 --> 00:19:52.360 that I used in this video. 00:19:52.360 --> 00:19:55.460 So don't forget to subscribe and support our channels 00:19:55.460 --> 00:19:57.960 if you wanna see more content like this. 00:19:57.960 --> 00:19:58.793 Enjoy.