Understand Rigging Forces: Vectors, Force, Torque explained.

welcome to Strider trees today we are talking about forces it's gonna be a little bit of a nerdy conversation we're going to break down vectors and torque and all this good stuff so that you can better understand how to take advantage of the strength of the tree so we're not breaking out canopy anchors that our lives depend on today this one's sponsored by Adler North America and the academy trained I'm here in the academy down in Santa Rosa where they do awesome trainings for individual arborists and big companies alike we'll check them out here as we get going but hopefully you'll find this valuable all right we're diving right in how many of you guys know what a vector is uh if you don't remember that from high school physics I can't believe you I'm just kidding okay nobody knows a vector is a more precise described a description of a force right we all have some idea of what a force is the the problem with Force as a unit in and of itself is that it's not really useful because forces are always applied in a direction right I I can't just apply a force I need to push on something you know Newton's third law every action has an equal opposite reaction I can only push longing something's pushing back so every Force has a direction and that is called a vector a vector is a force in a direction and in physics we will describe that generally as in with an arrow right and gen the magnitude of the force so how big the force is will generally be described by the size or the length of the arrow right and then the direction is the point wherever the arrow is pointing so we we have a magnitude and a direction associated with every vector and that's important because when we're dealing with working around in a canopy where we're dealing with climbing around the tree my body is a weight and I my weight exerts forces on the limbs on the tree as I'm moving around and the hope is that the forces I am exerting are always less than what the tree can tolerate now there's one other concept to consider besides just the vector and that is torque now torque is a useful measurement but it refers to forces that are associated with something that has a pivot point so a torque is is a force in a Direction but against something that has uh that is fixed on one side generally so Torx always refers to some sort of rotational rotational movement for example if we come over here here's my little makeshift Branch right if I take my finger we'll just pretend this is a vector right this is a vector of Force if I exert a force down my finger is is a vector of force in the downward Direction I am creating a torque on this limb and now as I you can see the more Force I exert the more the limb deflects from its resting position and so this gives you some idea of how much force and intuitively we know this right like I pull harder Branch bends farther but it's actually a very very precise Association and all of these Limbs and all of the wood and all the structure is designed to be able to tolerate a certain level of deflection certain level of torque but in some orientations that force is more tolerated more easily tolerated than others for example if I push instead of pushing straight down here if I instead push kind of down but also kind of in so I'm pushing at this angle I can push much harder with and it's going to cause less deflection uh same thing if I push straight on I'm going to use my thumb because a little easier I'm pushing straight onto that branch and it's not actually deflecting at all and I'm pushing way harder so it's a bigger Force Vector but because of the direction of the force this limb is much more able to tolerate that that load that that and because it's generating no torque right so I'm going to talk a lot about torque because torque is what tends to break branches when you've got a limb when you've got a spready canopy it's torque that will cause this thing to break not so much force in line with the grain of the wood wood is super strong in compression right here's like hyper simplified Branch right here now anyone who's ever broken a stick knows that you don't break it by pushing it together right I'm generating a force this way a vector this way and force it this way Vector this way and as I squeeze this this does nothing I cannot crush this Branch right but if it were fixed on this side and I put apply a torque a force Vector in One Direction everyone knows this will break or conversely let's just say I apply torque on both sides and I support the Middle Point here I can break that fairly easily with a fairly light Force so wood is strongest in compression and the idea behind building a good canopy anchor is to minimize the torque on our on our anchor and to maximize the load the the vector of force that my body is generating we want to maximize the uh that the directionality of that force in compression along the branches so let me try that first here and hopefully it'll make a little more sense uh I got my pen Okay so my brother Drew this beautiful tree here this is like a classic spready canopy one of the ways I might enter let's just say we're doing a tip reduction we've got a little house over here right and this Branch it looks like it's going to break off and it's going to fall on the roof of this house that would be bad but this is a hard place to get to because my high ties are way over here so if I put a line in the tree there's obviously a lot of ways that we could set a line let's just say I go for the simplest one I need to cut this little Branch out let me put a line right here and it's going to hang straight down I managed to isolate the branch let's say and I did a canopy anchor straight up well here's the problem with that simple system right just like this branch that I've got over here that we were talking about with the torque when I climb up you know little climber dude going up this rope right here what that's creating his weight is a force in the downward Direction equal to his body weight plus all of his gear and all of that well that's like me putting my finger down on the edge of this Branch over here right that is creating a torque here a significant torque because the other factor involved with torque is how long is the branch how much leverage does he have to break that Branch now not only is his body out here all the brush all the green leaf there's a lot of weight already on this branch that is in this downward Direction because of gravity so this yeah it might work if that branch is really thick and sturdy and strong and then it's an oak and maybe it's been pruned before so maybe it's fine but it's not optimizing the ability of that Branch to support your weight so let's just say how can we make it better well what happens if I instead of tying up to here what happens if I instead start and I shoot my line I shoot my throw line up and over the whole canopy right so I'm a guy down here he's got his little box and he shoots his throw line and it goes It goes behind that Branch through there goes up and over through that Union over the top and then comes down through all these guys and lands in that same spot well all of a sudden when he climbs on this rope right here he's pulling tension right but no longer is the tension being applied to this brown Branch this this one directly over the building in fact there's almost no tension being applied because all that branch is doing the branch is only pushing out on the Rope see how the Rope has got this big curve all of these branches all along the way are pushing out on the rope and what that's doing is that is redirecting the force so that branches remember just like this little just like our little bamboo they push out really well they just don't they they flex and break so if you route your rope like this then you can kind of optimize that to some extent so we're going to go back over here to this branch and I'm going to do a little bit of a demo here so to kind of exemplify the idea here I've got my load this we're going to pretend this rope bag is a climber you know this is a fixed weight if we look at this guy and I drop this rope right here you can see how much deflection that creates right we've deflected that rope you know a decent amount whatever that is five inches over this length now instead of that would be that was like when the climber tied in directly at the end of the Rope well now instead we're going to pretend that this rope is anchored up and over like it did before and now instead of being tied directly to this I'm going to tie into this rope it's going to be it's going to be redirected here just go like this hopefully you guys all know your slippery sheet Bend here all right so now I'm we're going to be on the same part of this Branch right but when I lock that on there look at how much deflection that gets there's almost no deflection so it was all the way down here before and now it deflected just ever so slightly see if I lift this I'm actually picking up the whole thing with that that's where it sits normally that's where it sits with that branch now I'll show you one more time here with the Rope itself now would be a great time to tell you about our sponsor so here we're going back to this so I'll even bring this rope a little farther in and there's the deflection so it's the same weight that is being lifted but instead of tying directly to this we've redirected the Rope up and over so in the coming videos we're going to talk a lot about redirects and redirects are primarily designed to essentially emulate what we just did here where we're redirecting the force on our canopy anchor so that we're not torquing a Long Branch we're instead loading it in compression like which like what is happening here in this scenario either way the climber gets up to the same spot but in the second scenario I'm putting a lot less stress on this branch that you know we're trying to remove anyway obviously it has stress on it that's why we're climbing it so optimizing our vectors and our forces and the torque is all designed to hey let's make preserve the tree let's make sure our anchors don't break up from under us and that's and that's what this is about

Channel: Strider Trees

Views: 3,695

Keywords: Arborist, How to, Rigging, tree work, climbing, tree climbing, techniques, gear, reviews, equipment, petzl, tuefelberger, notch, edelrid, rock exotica, rope access, forestry, timber, faller, zigzag, akimbo, unicender, SRT, DRT, MRS

Id: 7mL6I_7Ggzg

Length: 10min 55sec (655 seconds)

Published: Thu Aug 17 2023