The Physics of GriGri | When does No-Hands Belay Fail?

[@engineeringMemellionaire]

a small correction to the physics here - there is a difference between static and dynamic mu, because friction is higher when two surfaces are not in motion relative to each other. Dynamic coefficient of friction is not equal to static coefficient of friction, so as soon as a rope starts to move through a gri gri , the friction is slightly less than when it is fully arrested.

[@HardIsEasy]

Yes dynamic friction is usually lower than static, but in the formula I used what's been tested by experiments. You can find more info here: www.ropelab.com.au/files/physics.pdf Page 86

[@Doctor_Yuri]

Its not a meaningful difference as both cases show the same relation between the tension applied and the torque created across the device. If either µs or µk give the same relation, then its normal to drop the case outside of numerical analysis or further relations into a dynamic system.

[@xxrgxxcasco]

this might make a great difference if there is slack on the rope from the grigri to the climber, in a way that by the time there is force on the rope at the grigri, there is a considerable speed, and since you use the larger coefficient, the grigri is supposed to engage easier.

[@Doctor_Yuri]

@@xxrgxxcasco Yeah but thats using dynamics at that point, and the entire presumption of this analysis is using statics. It would overcomplicate the model and at the end of it all it could simply be replaced by some coefficient (lets assume phi) to be placed alongside the tension relationship. Still doesn't change the overall model, only numerically. By the way, I am a physicist (but work as an engineer), though I try to not be presumptuous.

[@xxrgxxcasco]

@@Doctor_Yuri No need to explain yourself as a physicist, you certainly write the part leaving physicist trails. I agree with you entirely.

[@jellekolenbrander9156]

As a Dutch climbing instructor I am going to show this to every new lead climber that follows my course. Thanks for the in depth information!

[@HardIsEasy]

Hey thank you so much!

[@henrypowell1402]

I work as a Climbing Instructor and every time someone asks why I advise them not to hold the climber side and the brake side of the rope parallel above the grigri I wish I could sit them down to watch this video, so many of your videos explain things that people don't usually have the time to explain, teach or read into. A great service to the climbing community❤

[@TheWayThePath]

The gym i sometimes climb at have floor anchors attached to the top rope and grigri. They are anchored low and there is literally no way to belay the proper way ( unless you are kneeling down) They advise and continue to advise parallel rope method that you mentioned. As far as I know thay have been operating like this for years with no incidents. I’ve been trying to find out more info on this topic. Seems like the grigri will hold when held parallel( tension on the brake end or course)

[@Gecko2601]

@@TheWayThePath Did you find out more about that?

[@daan_me]

The quality of this video is so insanely high, both in production as content. Keep it up man!

[@YannCamusBlissClimbing]

+1 . Probably my favorite grigri video of all time!! Thanks Ben! Can't wait for the next one with other belay devices 🙂

[@skip1860]

F anyone that uses Content to describe a fucking video

[@lazycat5108]

The best GriGri video ever. Definitely broke my misconceptions, I too thought that probability of locking goes up with the force on the climber's side of the rope. Thanks for doing this work, you rock!

[@andrewhunter6536]

I think it technically does since there is a term he neglects in the theory which is the extra tension on the brake side from the force needed to accelerate the rope. F=ma so if it free fall is assumed (big simplification I know) and the hanging rope weight is 80g then it’s about 0.8 newton

[@jonnes__4657]

So many climbers are often in danger, and they even don't know it. .

[@timwildauer5063]

It’s vitally important for the entire community that we learn all the possible modes of failure. If we know when and how they fail, we can put proper safety checks in place that will ensure these failures never happen. Thank you for working hard to make sure we all stay safe!

[@PS2Reviewer]

This is more in depth and well made than my thesis.

[@roboterson]

Love the safetey crocs you are wearing while doing the weight testing. Stay safe!

[@HardIsEasy]

Proper gear is important in lab env

[@VideoKillah]

I'm so happy this is the first comment

[@NoclockMinecraft]

Glad you wore your crocs in safety mode while dropping weights on a crashpad ! Great video as always, thanks for doing the work of putting the theory to the test of reality !

[@HardIsEasy]

Yea safety equipment is important:)

[@jorgesc8234]

Bro! This is dope! I'm a physicist and you communicate exponentially better than lots of physicists themselves. Keep climbing and keep learning! Love your videos!

[@andreaswolffmusic]

I'm a climbing instructor from Germany and I've learned so much in this video. This is a perfect example why people should never completely rely on the belaying device triggering automatically. Thanks for all the great explanation and demonstration. Keep up the good work! :)

[@vinceburris2538]

Glad to see a new video from you. I like your teaching style.

[@oriolmarti3108]

I'm sure this will just be another common comment, but this video is absolutely fantastic man. If almost every video you make is a 10/10, you have surpassed the level in this one, congrats and thank you for this content.

[@HardIsEasy]

I appreciate every comment, not only for the algorithm, but it's really nice to feed back to my energy to create more ;)

[@avichi2]

as a mechanical engineer and aclimber i would to say, very good job ! showing forces and moments in a clear and accurate way. starting from first princibles and working your way up to theory and expirament. very impressive

[@brianthrom6858]

@10:10 the rope starts slipping through with sufficient enough velocity that you’re getting a sort of inverse chain fountain where the momentum of the moving rope is throwing the rope above its defined pivot point leading to the rope settling into the ideal position to continue slipping. That fall could have been indefinite Edit: time stamp correction

[@jeldrikhartmann531]

Did you watch that video by Steve Mould on this? Noticed that too

[@brianthrom6858]

@@jeldrikhartmann531 100% where I first saw the phenomenon

[@Blue-pb7kz]

This is super important information I think - a while back, I saw some very young children in my local gym who were belaying with grigris but holding both sides of the rope together in the same hand, parallel. I was worried it would stop the cam from engaging, but when i went to ask other climbers about it, they told me I worried for nothing and shouldn't say anything (the children were supervised by gym staff, who know better etc etc). They even said, these children are so lightweight that it's a struggle to even lower them after the climb, so there's no way this is dangerous. But I still felt like it was dangerous to hold the break strand parallel to the climbers side. This video shows why that might be! So thank you so much for sharing it.

[@liebscher-hatsbracht7079]

It is true that some children are so lightweight its hard to get them down after the climb. Still I consider it a bad idea to let them use bad and possibly dangerous belaying technique. With quite a high probability those children will grow and get heavier by time. Or other children that are already older and heavier might see that technique and think its the normal way to belay. Anyway, who decides at what weight you should start to belay properly?

[@boerenkoolmetworst]

i dont see how you can imply from this video that holding the brake strand parallel might be bad? It only implies that if you don't hold the brake rope and certain other conditions are met (i.e. climbers rope going vertical, you use skinny rope with low friction, etc) then the cam might not engage. Brake strand parallel on a tube-style device is a different story of course.

[@scottnon9779]

Really excited to watch the video, i feel like there are so many misconceptions about the grigri and its safety in a hands free scenario!

[@oldmanbeta]

Wow, amazing video. The production value was great, but the carefully documented (and clearly presented) results were eye opening and super valuable. I always assumed the camming action would be a function of the force of the falling climber and/or the brake strand resistance. I never would have imagined it was *just* brake strand resistance.

[@HigjiH]

Thank you! This is the kind of information I use in my job as a RAT SL. So many good videos 🥳

[@iain_nakada]

Awesome video, as usual. And I swear the production and editing are getting smoother and smoother. Actually really psyched for the next one on the range of self-locking devices. A subject I'm really interested in and follow closely.

[@olivierlaborde7887]

as a mega jul user. im really curious what he has to say

[@whelmking6497]

Ben.. this is exactly why I am happy to be a monthly Patreon supporter of your channel. This is simply the best climbing information on the internet. For me, the big lesson (as a grigri user) is that the brake hand is not only being used in case the cam doesn't engage, but that the break hand creates the friction required for the cam to engage. This is such valuable knowledge.

[@HardIsEasy]

Ah, this takes time to make, so having people like you supporting me is amazing, puts my pressure on finances lower and helps me to focus on investigating and creating. Thank you so much!

[@Monscent]

Well, thats not quite the truth though. Every time i climb i yank the rope at my partners grigri before to extra-confirm that its fed correctly (its just part of the standard check). My partner never holds the brake line in the "correct position" at that point as we are doing the partner checks. And yet every time it engages, never failed so far in hundreds of checks. Can it fail? Im sure. Will it? Probably not? Should you hold the brake line? Of course. Is the extra safety still good to have? Yes.

[@fabian624]

@@Monscent I do the same, also as part of the regular partner check. I may be wrong here, but I think it engages due to the massive acceleration you achieve when you yank the rope during the check. This acceleration causes the brake rope's mass to generate a higher resistance force than it does with its own weight (i.e., under 1g). But you probably wouldn't get that acceleration when your climber falls because their theoretical max acceleration of 1g is reduced by the quickdraw friction. So the brake rope wouldn't put up the same resistance as in the "yank test". I.e., you have to put up that resistance with your brake hand. If you "yank" a bit more slowly in the test, it will slip (at least it does for me).

[@mastheadmike]

This video is so helpful beyond the scope of the grigri - your curiosity ended up illustrating real world examples of physics and engineering so beautifully. I hope it encourages kids to study them with more interest. Well done.

[@Shrimpycus]

Another amazing video, backed by science! I hope you realise you are literally a lifesaver by bringing this to our attention

[@colasdavid953]

What a piece of work ! Thanks a lot for such dedication into this topic !

[@pavelnadvornik5337]

Thanks! Even though I personally dont use a grigri this is such a great, complex and easy to process information packed video (as well as your other videos).

[@HardIsEasy]

Hey thank you so much Pavel!

[@angrybirder9983]

I have a hypothesis on why it is more likely to lock when the rope is yanked hard: During a fall, the rope gets accelerated. This acceleration should be the highest at the beginning of the catch, when the rope is under tension the first time and the rope on the belayer side goes from zero to the speed of the falling climber very quickly. And in this case, the force on the brake side isn't just the static weight, but also the force required to accelerate the rope. In a static scenario, the force is F = mg. For a rope accelerated by a, the force is F = m(g+a).

[@IAmMaarten]

My thought exactly, it's not (just) the weight of the rope on the break side that matters, it's also the force required to accelerate it, which is probably why a sudden hard pull is more likely to engage the cam than a gradually increasing speed. Regardless i think the main message of the video holds really well, and this is fantastic work to show how and why it is important to provide a breaking force even with assisted breaking devices

[@mzkabn]

precisely!

[@leoingson]

True.

[@adventureawaits6923]

Thank you for making this video series, keeping people safer with more knowledge about gear is a pretty awesome thing to do, keep on keepin on!

[@hii4973]

Amazing video! Very well researched and also great videography to show what you are explaining

[@lisa-koschat]

worth the wait- always. Great work. And now I have a video to share to all the ignorants that wońt believe that how they use the grigri is wrong. Thanks a lot

[@drstrangelove85]

My girlfriend after 10 minutes of the video, shaking her head: just hold the stupid dead end of the rope.

[@n085fs]

A Blake's Hitch can be put on the tail end to ensure the climber does not fall to the ground even if the climber becomes unconscious.

[@ottard]

Wow, what a great video! I'll have to watch it a few times to wrap my head around it all.

[@Ranger629]

11:53 man's gigantic balls for trying out this experiment for the sake of all human life. Mad respect.

[@Engineer4Free]

Great video my dude, very well done 🙌

[@philippfinke458]

I really like your videos. You spent a lot of time investigating to find the drawbacks of the Gri Gri. This will help a lot of people becoming better belayers. Also, perfect explanation of the physics involved. Thanks for all your effort!

[@gusasso]

The feeling of a new video is like a new season of my favorite tv series kkkkkkkk niceeee

[@ruhrml]

Ur work helps many climbers and enthusiasts around the world to learn more. Thanks!

[@philipparnold19]

This video is pure satisfaction to me, sendig it to friends who won´t listen about not holding the break strand, too 🙂 Thank you so much!

[@BKK505]

Thanks! this is very good infomation for the GriGri , now i understand how it work

[@HardIsEasy]

Ah thank you so much!

[@jnonymous]

I just realized you are the same guy who created the video about the effects of dirt on climbing rope. Your videos are fascinating and educational to me. Knowing how to keep ourselves safe empowers us to enjoy ourselves in the moment. I would enjoy more content like these last two videos!

[@joerivanlier1180]

I've never been in to climbing or heared of a grigri, but man the KZbin also was on point, I loved this video. It was both good in science, production, safety education and the jankieness I love. You had fun and hopefully saved some lives.

[@marcushill78]

Great video, thanks for your hard work. I bought a Revo instead of a Gri Gri, can't wait to see your next video to see how it performs.

[@HardIsEasy]

Thanks and yea working on that video as you read this msg ;)

[@Fraizedesbois]

As a revo user I can tell you that for lead belaying it’s great as it gives rope like a charm. But in my opinion it can be scary in some situations as the revo only locks once a certain rope speed is reached (speed of climber falling) ; So in some specific situations it can be tricky and not lock on time (ie: top rope on slabs ) or not lock at all if fall speed is slow (ie:positive incline)

[@EricNietofilms]

I liked this video a lot! for a safety recomendation, I would separate more the 2 pulleys on the beam when you are doing this, having heavy weights falling just next to your head sounds a little bit risky 😅

[@HardIsEasy]

but but.... I would have to walk more ... :))) haha thanks 👍

[@ryenschimerman2127]

As long as we're not returning to the days of @HardIsEasy creating a fall while holding a sharp knife, I'm good. Those got my anxiety up :p

[@NippyKindLangur234]

@@HardIsEasy dont get hurt on our behalf

[@jonnes__4657]

And wearing no safety shoes sounds also risky. .

[@samuelmellars7855]

Yes, I was going to say something similar! Although I think his head is reasonably safe (the weight is unlikely to swing that much sideways as it drops) I was very worried about how/where the weights would bounce to after hitting the floor! Also, spreading the pulleys out would be a bit safer on the beam, especially if the weight is dropped as close to a pillar as is safe, and the belayer is as close to another pillar as is safe!

[@TD-ne2mi]

Thank you for your effort! I learned a lot :)

[@HardIsEasy]

Hey thank you so much!

[@belaygear8889]

Great video with great insights and great entertainment. Love it! Also, can't wait for the follow up! Doing a lot of similar testing with belay devices. Using my findings for teaching a better understanding of the different devices. And in every workshop there are at least a few usually experienced climbers, stating "Grigri grips the rope no matter what!" and "Grigri is the best device! ... always!! ... and for everybody!!!" (exclamation marks included). The only device i could not outsmart was the REVO. Looking forward to see your findings! Keep up the great work. It makes our favorite sport a safer one.

[@TheS4ndm4n]

That's an interestin effect that, once the break side of rope has gained enough speed, it will no longer engage even when it moves to the "front". This seems a lot like that chain fountain effect, that steve mould is so obsessed with. Also, I have seen so many plugs for brilliant, but yours is by far the one that made me most curious. Well done!

[@jadefalcon001]

What a fantastic video! This is a terrific example of applied newtonian physics. Love it!!

Very high quality content, as always. Thanks!

[@HardIsEasy]

Thank you so much Jeremie, and extra cheers for long term support!

[@n2b998]

Great instructive video. It demonstrates that explaining how something works is a great way to train someone to use it well.

[@nicod1886]

The amount of time and knowledge he put into this is incredible. Thanks man!!

[@duskjester3027]

Good video, for a non-physics channel this is remarkably well explained. I'm impressed your real world results lined up so well too. I was watching the physics chapter thinking "yeah sure if you have everything *perfect*" but no way in real life... I was wrong! I haven't belayed with a GriGri before but I'll definitely treat it with caution!

[@audiojck1]

As you should have a hand on it anyway, the GriGri is pretty safe. There are not a lot of belay devices that have less failure modes than the GriGri, but let's see in the next video.

[@joseramonguillenlopez2272]

Your videos are incredibly valuable for the climbing community. Great video as always, thank so much and congratulations for the amazing work

[@ilyaSyntax]

perfect sponsorship segment. First ad I actually appreciated seeing -- applied to the content and non-intrusive. Thank you Ben for all that you do

[@HardIsEasy]

Awesome, thank you!

[@eddymofardin9294]

Thanks!

[@linegrip]

Fantastic video Ben! 👍 So nicely done, clear, on par, extensive, and comprehesible... truly a masterpiece! WOW 😯

[@olakoppe]

I was very curious on how the physics explenation in this video was going to be, based on your instagram posts. But I have to say I'm impressed by the quality, and think you nailed it! Good work

[@someoneelse1904]

Amazing video! Some really interesting outcomes there.

[@WeaselBeeH]

Bro, you are the reason why I got a patreon account. Keep the good work up, we are all impressed here by your diligence

[@HardIsEasy]

I appreciate that!

[@projecteer4498]

This is great, especially with the balance between physics/demonstration/practicality. Will definitely be rewatching in the future and learned a lot

[@josekasanchez5245]

Thank you for this kind of videos. Necessary and important

[@JourneeDecker]

This is more in depth and well made than my thesis.. This is more in depth and well made than my thesis..

[@sofussverressnnfinne204]

Great vid, Ben. I might try to use some of this GriGri knowledge to get smoother with paying slack as well!

[@johnarinehart]

Thank you so so much for all of this work that you are putting in to test and find what can go wrong and how. I wish more people would watch your videos. I share them with my friends to try and spread the word. I like to get into this nerdy details of climbing 🤓

[@BMacG26]

Nice!

[@pymzorr]

This is insanely good. Thanks for all your work !

[@tytoalba19902]

Love your content man, keep going. Well explained, great production and topics of broad concern.

[@ripperkon]

Thx for the video. This is again some valuable content!

[@Sam-ss6yn]

Thanks for the camera shot at 11:51 😏😂

[@mmlei7540]

so excited to see the next video comparing different devices. thank you for the in-depth explanation. i get worried with grigri that it teaches people to be lazy with the brake strand, compared to like a tubular belay device.

[@UkoZJ]

Would it be interesting to test the gg in an inverted position as in solo lead climbing? Quite a niche scenario but quite useful 😅 Incredible production with slow motion and zoom-in!

[@eriksabo8102]

Usually I never comment youtube videos but could not help myself, this is just awesome work! Thank you!

[@bjorn9875]

Very interesting! I never thought that speed would have no impact, but it does make some sense. Some googling later and I find that the entire equation used for friction is actually wrong... I found this: "Perhaps the most important point to get is that solid-on-solid friction is a really complicated phenomenon, and the simple approximate rule F=mu*N used for it in elementary mechanics courses has no fundamental justification, even though it often works pretty well." But no matter if the formula is correct or not, your testing shows us to never actually trust a grigri (or any device that is not made to be permanently/manually locked)! Thank you very much for making these videos!

[@junuhunuproductions]

Amazing scientific overview! This is probably the most rigorous study on grigri available to public 🙏🙏🙌

[@andm6847]

Thanks for your continued videos on the Grigri. This is extremely relevant to all of us. From my personal experience I have never seen a Grigri slip that way though, even the Grigri 2 switched to lead mode and with a 9.2 rope. However, I would never let go of the belay rope or having a long sling of free rope in the belay hand. But it is very scary to see that this can happen and I will be even more careful because you can easily cause a ground fall in the beginning of a climb if you somehow cause the Grigri to slip for 5m (~15ft).

[@Gui_M]

Great video. You're research went far into the physics involved behind all this. And the way you explain makes it very understandable for everyone. Can't wait to see the next video and your experiments on the others auto-locking devices. 🧐

[@darreno9874]

When I was taught to belay the golden rule was to never let go of the rope. Why some climbers are so cavalier with the life of their friend I don't understand. Keep up the great work. God bless

[@janosadelsberger]

I don't think it's important to the bottom line of the video but it would be interesting how the slot of GriGri's cam plays into the physics. The rope gets squished into it so there has to be some effect on the friction. Anyway, I absolutely love the nerd stuff - keep it up and I'm hyped to see the other belay devices!

[@xxrgxxcasco]

The acceleration at which the climber side of the rope is pulled DOES affect if the grigri engages, because there is a resistance on the brake side of the rope to start moving (1st law of newton), so there will be an extra tension on the brake side of the rope due to that. If the acceleration is VERY high (like, yanking the climber side of the rope), the grigri is much more likely than if you have a low acceleration on the climber's side of the rope. Adding weight will not affect the acceleration (which will be a constant 9.8 meters per second square whenever there is no slack on the rope from the grigri to the climber). If you give a good meter of slack of rope, by the time the rope starts to corner around the grigri's cam, there will be a rope speed (aka kinetic energy) to engage the grigri's cam. I am by no way condoning no-hand belaying with ANY belay device, I am simply imputing a little bit more to his great job.

[@jakob8741]

Yes, otherwise we would see much more accidents with grigri (or just no one would consider buying it.) One thing you should really not do, is to have the climber resting (or yourself in rappel situation) and think "hey, cam is engaed, lets rest too" and take the brake hand away. Any short unload of the rope will lead to the demonstrated situation.

[@muchachonechvile5078]

Great, thorough video! Loved the physics explanations and the time taken to make this video, keep it up 👍🏼

[@wheeeeehee]

Danke!

[@HardIsEasy]

Thank you as well!

[@xzygy]

I used to set routes all day solo on grigri with buckets full of holds on both hips. Never once had any slip. I feel like one would need to be either very specifically ignorant to how the device works, or actively trying to cause slip. Have trusted this device with my life, would again. Fantastic piece of kit.

[@adebh]

Amazing video, yet again. Thanks Ben 🙏 Cannot wait until the next one 😃

[@andreboily8645]

Amazing video, from the climbing information to the physics its a masterclass in merging real life with school and making it super interesting

[@schluppvomgrunenstern7394]

As always an awesome video. Keep going. Can't wait for the upcoming video.

[@ChadSpence]

I'm glad you went deeper into this topic! Great work putting this together.

[@windsweptmtn]

Super high quality video, this was awesome!

[@lil_laxho2633]

Super engaging stuff man! Love it thanks for your dedication

[@buckcorrigan9595]

Great video ! Glad to see you're back, I was wondering what your next video might be...

[@Carlsbergbad]

¡Gracias!

[@HardIsEasy]

Gracias tambien!

[@alekseynalivayko1140]

Thank you for what you doing. Ill show this video for all my friends

[@wienerwoods]

I'm no expert, but I belonged to a climbing gym for a while. I seem to remember that the #1 rule is that you NEVER let go of the tail end of the rope on-belay. Never. You don't allow any slack in it either, and you hold it in such a manner that you can immediatly lock your belay device using downward pressure. Am I missing something here? Are there climbers who think Grigris are fool-proof hands free belay devices? Are they marketed as such? If so, that's terrifying

[@eager400]

That's what I understand too, never let go of the brake side. I think people get complacent and then something like this happens and they blame the device. I've seen some reckless belayers before and they just rely on the grigri to work without fail but they are using it improperly. This video was a great example of the simple never let go of the brake side would get rid of this issue.

[@studious0782]

Love your videos as always. Excellent job

[@charanvantijn541]

Thanks so much. I was wondering about this for so long. You've answered all my questions. Super!

[@Rel1193]

Amazing video! Will definitely share with my climbing partners

[@royalmorris9257]

This is a great video and I appreciate the graphics to explain the physics. My physics math is good but by physical intuition is awful so this was really effective in helping me understand how the grigri works

[@jennifersolis992]

So good! Thanks for all this detail still easy to understand

[@dack42]

Excellent video! I have personally witnessed a grigri slip in real world use. The person belaying was inexperienced. They were lowering a climber and started going too fast. They let go of the grigri, but it didn't lock. I don't believe they had been instructed to keep tension on the free end of the rope. They had been told the grigri would lock if they just let go of everything. The climber did hit the ground. Thankfully, they were not very high up when this happened, and had no major injuries.

[@c.a.c.coseacaso4385]

WHAT A VIDEO, 100 times better than every phisic class at university

[@andreasmagnusandersson9235]

High quality content - I imagine it to be really interesting to deeply look into how all this stuff works! I am very happy that you show all the testing and physics - making your videos not just your opinion :) I feel like the quality went up a lot! In your old video for example named something with ninja method for tying the figure 8-knot you say something like that it is better because it is faster to put thread the rope on the right side (or maybe left side) of the belay loop, without explaining why - an example of your opinion as I see it. Now your later videos explain much more in detail and with good non-subjective arguments for what you are explaining. Also the ninja method video was as I see it messy in structure and you had to sort of see the whole video to figure out how to tye the figure 8-knot the ninja way. Your later videos follow in my opinion a much better timeline for explaining what you are telling us viewers :D Keep up the really good work - I am looking a lot forward to your next video with the other assisted belay devices and how they fail. I'm interested in this both as a private person and as a teacher at an outdoor life high school in northern norway looking to buy assisted belay devices for our climbing classes.

[@HardIsEasy]

Ah thank you so much for the feedback ;)

[@radostwaszkiewicz4982]

About the speed dependece: when rope moves around the corner it has to change velocity so we need some centripetal force (velocity dependent!). This might make up for the missing few newtons to lock things in place

[@dgiroday1]

Great video! This helps address peoples positions that it is ok to take the brake hand off the brake end of the rope!