HillBilly Science in 5 min. It’s Not the AXE WEIGHT, But MOMENTUM That Chops Wood!
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- เผยแพร่เมื่อ 14 ก.ย. 2017
- It is not axe weight that does the chopping wood, it is MOMENTUM, which is the product of MASS and VELOCITY. With any given axe, you can change velocity only, to increase momentum cutting power. Accompanying blog post skillcult.com/blog/2017/8/29/c...
Watch a deeper video on this subject: • Geek-Fest, Practical A...
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It is often said that you should "let the weight of the axe do the work", or "let the axe do the work". While those sayings are meant to teach important lessons, they are innaccurate and foster no understanding of the problem of momentum when using an axe. Momentum is what chops wood. The momentum of an axe head is a product of it's combined Mass and velocity, so it can only be changed be changing one of those two variables.
We can choose a heavier axe, or we can swing the axe we have faster. When chopping down trees or working with an axe in the woods, the weight of the axe in our hands is fixed, but we can change the velocity at which the axe is swung to increase or decrease it's momentum.
Momentum can be thought of as potential to do work. A still axe head, heavy or otherwise, can do no work. A moving axe head embodies a certain amount of energy that varies with it's speed. Another way to look at the problem is through the property of inertia. Interia means that a still body wants to stay still and a moving body wants to stay moving. When using an axe, we first break it's still inertia, which requires energy, then we swing the axe more or less hard to create what you might call forward inertia. This moving body has momentum, again as a product of it's combined mass and velocity. The tree or log we are chopping has the property of inertia in that it does not want to move. When the two collide, hopefully work is done, depending on strategy, aim, the condition of the axe etc.
If you look at axes as a spectrum from very light to very heavy, the two extreme ends are going to be somewhere between unuseable and unsatisfactory. In between there is a happy zone where you can get work done efficiently by swinging light axes faster and heavy axes faster.
This understanding of how some of the basic physics of an axe works, could help develop or refine technique in limbing, felling and bucking trees. But novice users should be very cautious about pushing the develpment of velocity too fast. There could hardly be any better way to get oneself in trouble with an axe than to chop ahead of our skill level and try to apply too much power. Concentrate on accuracy and strategy. It doesn't matter if you hit the wood hard if you hit it at the wrong angle or way off target.
Don't chop like a meat head. Get the axe moving, then let it do it's work. Don't try to push or force the axe through the wood, that doesn't work very well. Create momentum by increasing velocity, with the least movement and energy you can, then let the momentum of the head do it's work.
"I'm not a phisikist, or a sciencer..." Love it
"phisikist..."
*Blinks hard
Don't let him fool ya...I learned more about physics in 5 minutes than I have learned in a life time..,As said...information overload!!!Much Respect....
"I could leave the axe here all year and the tree still wouldn't get cut down."
Dude, had me laughing.
"I am not a Physicist or Sciencer by schooling"
Kind of seems like it to me :
-has an idea
-seems to make sense
-interact with the world to see if the predictions happen
-is willing to have a dialogue and update ideas if necessary
As one hillbilly to another, seems a decent Sciencer to me.
Better than the Fauci even
I come back to these videos fairly regularly, they are good stuff.
Thank you for being a thinking man. I wish it were more contagious.
That would be nice. Hopefully it is. It takes time and intention to learn critical thinking and we can still only get so good at it. We're pretty dumb.
readpsalm3
Nice video. I like the idea that the work has been done once the axe hits the tree. I personally like heavy axes 4-6lbs. They just feel better in my hands. 👍
Always a pleasure to watch your videos. Thoughtful, insightful and with a sincere intention to educate.
+SkillCult - I laughed so hard I farted with the sciencer bit! Great info with a healthy dose of your dry humor! Much appreciated my friend. Well done!
Maybe I'll go to science school...
SkillCult - That was some seriously funny shit! Keep doing what you're doing brother, it's awesome!
The energy is proportional to the mass times the velocity squared. Twice the speed means 4 times the kinetic energy. Twice the mass just gets you twice the energy, so you get much more kick out of increasing the speed.
Right, but what is the energy economy of all that. Probably very hard to measure, but I doubt there is any huge free lunch in that extra speed if energy expenditure is calculated in.
@@SkillCult E=1/2*m*v^2
The goal is to maximize the energy stored in the moving axe head at the moment of impact with the log. This has much to do with human physiology, not just mass vs speed. For myself I prefer a 4.5 lb axe on a 32" handle. I throw the axe head up at a near vertical angle, and then pull the handle in and down to swing it back down to the log. I get a very fast axe head this way, and can split clean wood extremely quickly. A 7lb maul would be sluggish.
Excellent video Steven. This also explains why you don't need a 'fish club' axe handle as the handle is only there to accelerate the axe in free air (where there's little resistance) and then to hold on to, steer and control the axe head when it hits and does its work.
Great stuff!
Thanks. Yeah, those fish clubs lol.
BTW I love your videos. New to the axe thing so it has been really helpful.
Please forgive and overlook any minor errors in terminology and physics principals. I only care about the practical principals and I believe that those are accurate enough. If not feel free to correct me. There are of course more questions that are raised by this examination, such as even if two momentums are considered equivalent, how does a heavier mass react when striking wood v.s. a lighter one. There are many factors that go into effective chopping. This is only intended to really examine one aspect.
The heavier head will keep its velocity for longer after the impact. The lighter one will hit faster, but won't have the same follow-through. Also, there's something to be said about edge wear and its connection to velocity.
Thanks, have been wondering about that.
SkillCult I applaud you for attempting to explain these principles with physics principles. Physics is key to understanding these things(and all things, really). Attempting to use physics is a great step in understanding what's going on.
That being said, I'd recommend that you watch the MIT 8.01 lectures. It will introduce you to basic mechanics. The professor is wonderful and I guarantee that it will help you in understanding what you do and help you to complete tasks more effectively. Calculus is required, but if you don't know that I promise that it isn't that hard even though the notation may seem confusing. Learning the basics of calculus is basically learning two ideas, which aren't too difficult. Don't be put off by the scary notation. I can send you links which explain it well, if you ask.
The problems that I have with your explanation is that it only uses the linear momentum equation. What you probably should be using as a model is the angular acceleration of the swing and the kinetic energy at the moment of impact. The latter is the most important, and it is dependent on the former. Use energy rather than momentum.
Your problem is actually pretty complicated and depends on a number of factors. But a good approximation is doable.
SkillCult here's a link to the lecture series.
th-cam.com/play/PLUdYlQf0_sSsb2tNcA3gtgOt8LGH6tJbr.html
SkillCult and I should add that you should feel free to ask me if you have any questions about physics.
Great coverage of an important topic. Thanks
Good info. I just found your channel and this is the first video I watched but not the last. Thank s
Cool, welcome :)
Any experimentation with trial and error with different data points acquired and presented in a conclusion is science
Great video as always!!
Thanks buddy.
Makes sense to me and as you stated there is variables to the math that can accommodate personel preferance taking into account for an individual's health, physical condition, muscle mass, body strength, stamina and endurance level's, in addition to types of woods resources availiable, and diameter needed to accomplish the end result of why the wood was needed.
Solid closing remarks!
Great video!
awesome video. I have a few thoughts, maybe you cover them in the expanded version:
one: the sweet spot of efficiency may have to do with balancing where you put your energy: a heavy axe requires more effort lifting, less effort falling. a light one, less effort lifting, more falling; to get the same energy to the target. when working over the long haul it's helpful for stamina to keep those efforts balanced as they use different sets of muscles.
two: at a certain point of lightness, you're fighting wind resistance to swing faster. I don't know enough to say whether that influences the point at which an axe is just too light to be efficient, or if limits on human muscle speed factor first.
the whole energy expenditure issue gets really complicated. Some people may be built better for certain types of work, or just be better at doing them efficiently. And how could we even measure. At some point it becomes almost too speculative to bother much. The issue is brought up a lot that increasing speed is more effective than increasing mass in the momentum equation, but that is an abstract, mathistic (I made that word up lol) view which tells us nothing about the energy required to increase any given mass and how that plays out. But, like I said in there, there are extremes that are just not going to work very well, whether it's a 3/4 lb head on an axe handle, or an 8 pound head. Sure, someone can do real work with an 8 lb head, but for most it's completely impractical. Within that zone of effective weights though, I think you have a point that one extreme or the other could make for less balanced work. It's an interesting way to look at it.
Paperweight with potential lol
wall stabilizer.
I grew up in the Mountains of Kentucky, one thing I’ve done a lot since I was 10 was swing an axe. It’s something I just get pleasure out of now that I don’t live in the mountains but I’m definitely the magic man of a bonfire. All of my friends are speechless watching me chop/cut firewood 6 or 7 beers in and only taking 5 minutes every hour to keep it running hot. I miss they days of waking up cold trying to get life out of only a few coals in a wood stove, splitting wood with a maul till I’ve got blisters on my hands. Something about chopping is one of the best experiences you can ask for. Something about taking an axe up and over your head, but still hitting the exact spot you just hit makes a man feel like a man that has his shit together.
Yeah, I've been that fire guy a lot too. Also just tending the fire as it burns and keeping it burning well, rather than randomly throwing stuff on and expecting it to work.
your equation lacks c, catalyst, in this case adding the catalyst coffee increases productivity exponentially.
Just added that.
You're a bigger sciencer than you let on. Your physickism is applied.
Here's a thought maybe historically felling axes were heavy because they were using saws to undercut and then the chopping the notch is closer to a splitting job where weight really helps drive downwards with gravity and with less issue of sticking and the fibres are severed
I agree with the broad strokes, but I would say in general you are better off looking at the kinetic energy vs the momentum. Both are related to velocity (momentum = m * v, kinetic energy = 1/2 m * v * v). However kinetic energy has velocity squared, so it predicts a higher change in penetration with increasing velocity.
But this is a kind of minor point to the general idea :
-get an axe head you can swing at a decent speed, with precision for a long period of time
If your head is too light, you will just suffer from penetration, and if it is so heavy you can't swing it at proper speed, you will also see decreased penetration, and likely excess fatigue/frustration.
Yeah, I'm actually not really interested in the strict science part, but just the observational hillbilly level and what we can do about it, i.e. swing faster or use a heavier axe. I actually figured this out and was telling my neighbor and he as like, that's momentum. When I made the video, I didn't even look up the formula, because it's not that relevant. It's about the grey areas and staying away from the two extremes. The rest is up to personal preference. It's easy to get caught up in theories and formulas. A lot of people point out that speed is a bigger factor, so more speed equals more gain in momentum than an equal amount of mass. But virtually on one (maybe just no one period?) ever mentions the energy efficiency of a human handling and accelerating an axe, and that is more what it's about than the formula itself. And of course you can assign a number to mass, but mass and velocity are completely different things. In the end, we have to actually attach ourselves to the butt end of an axe and go swing it to learn or confirm much of anything.
Best intro!
Been using ax since fifties great video
Place your hand flat on a table, gently rest the axe blade on one finger. Try raising the axe 1/2" and let it fall, then try an inch or two. You'll understand the work that can be accomplished with momentum in short order and have a shortened finger to boot.
Professor of the actual use of the Axe
Can you recommend an Australian timber for axe handles?
Thanks for your great advice
love your channel, but... I think you missed the point (aside from not using established defintions).
Which is: Is it more effective /efficient to swing a larger axe slower or a smaller axe faster?
This is where the correct definitions and maths can help.
with out brow beating the maths thing, Is it typically probable to swing the next smaler axe fast enough to offset the loss of mass?
As a gun guy.
In terminal ballistics it is observable that kinetic energy increases with a curve that favors velocity over weight. Not that weight doesn't play a role, heavier rounds tend to penetrate better due to their increased momentum. I'm sure the same concept applies. The key is in the amount of input necessary to generate the kinetic energy/momentum
But for sake of energy efficiency, would a lighter axe that took less energy to swing faster generate better results over time with less fatigue than a heavier axe (assuming the heavier would cut deeper per swing at standard swinging velocity assuming you controlled for edge geometry- at the cost of more of the persons input energy per swing). I'm strictly talking about cutting performance vs. user energy input.
Like how many times could you swing each axe before being tired and which axe would do more work for the amount of swings/energy input. This is assuming you could control for most other variables like geometry, handle variances steel quality etc. Etc.
Everyone is quick to point out that speed is more effective in the equation, but almost no one points out as you do that it's the energy input that matters more. I suspect that you are right, that for most people, an axe on the lighter side will end up being more energy efficient in the long run. but it also may depend on the work done and how much handling of the axe there is between cuts.
@@SkillCult yes i think you are correct. a heavier axe would be less energy efficient over a larger/longer task, But would have a higher potential for doing work faster. like cutting through a log as fast as possible in a timbersports competition or whatnot.
Basically, I'd think you can cut through things faster with a heavier axe. Thats one type of performance i suppose, with the other type of performance being less user energy drained for the same amount of work at the cost of time. So cut more wood for the same amount of daily energy with a lighter axe. Of course, the heavier axe would likely (not neccesarily, i think geometry plays as big/if not bigger a role) have an advantage in splitting as well which may be why they are generally preferred or thought to work "better"
bucking wood with an axe isn't something a lot of people do much of nowadays so heavier heads may be more marketable to your average short term user.
Loved the reply, thanks!
I am a physicist and also a woodsman. The energy E = pi(squared) F(squared)d(squared)/2m where m is the mass of the head, d the haft length and F the force you give to swing it. So you need a small head and a long handle for the same F. And so I put a .8 kg head on a long handle. But eventually the head explodes. The energy at the impact point is 50% more than the 1.2kg head they normally put on that haft,
Awesome, do it. Metal work is fun :D
I know this is an older video, but kinetic energy (Ke) and momentum (p) although related are not the same. In this discussion, it's momentum that is the important factor. In a collision (inelastic), Ke is never conserved, p is always conserved. Think of it like this, Ke is what makes the tree shake when you hit it with the axe. It's momentum that determines the depth the axe bites. It's the exact same thing with bullets. The Ke causes the damage, the p causes the penetration depth. As for your discussion with axe velocity vs mass and which one penetrates deeper, momentum is momentum once the math is done. They will penetrate the same if the momentum is equal. The frictional resistance based on sharpness and angle of the edge is more important than the light vs heavy but equal momentum discussion. Just my two cents from what I remember from college physics and playing around with bullet penetration testing on my own.
no
@@drdrwoland1975 yes.
OF COURSE, if there's no axehead momentum, there'll be no cutting (unless you can arrange for the tree to fall onto the axe head's edge).
But as you correctly state, mass is an important aspect of the action. In fact, the most important because you'll have no success with a NEAR massless axe head, irrespective of the amount of velocity you're ABLE to apply.
Thanks for your interesting videos.
13 seconds in, and this man has already earned this Like 👍🤣
"..because I want to see more people using more axes more better" ⭐
So, after ordering the slightly heavier much longer counterpart to your council boy's axe I found your channel and have been binge watching ever since. What I've found (in my comparatively limited experience) is that the leverage from a longer haft gives me a lot of power. I obviously can't measure it, but if you apply the same energy to the same head, you should get more speed as the radius from your off hand is longer. Granted you give some up because it takes more energy to accelerate that longer lever, but it still seems more favorable in my experience. It seems like you favor a sub 30" axe? Is that correct and if so, why?
Yes, advantages and disadvantages with the long handles or short and light or heavy. I've just always used light short axes, so I'm comfortable with them. Also the kind of work I do. Diverse tasks in the woods. The maneuverability is nice.
That makes sense. Come to think of it, I may be a little biased the other way growing up around bigger farm axes that were never used for felling or bucking. Maybe also a little sore after buying a small forest (guilty) last year and discovering that it's not an actual laser beam.
Rob Zombie knows his axes lol.
Dis is amazing.
Hey skillcult! What kind of axe is that? The one with the chalk on it?? Looks beautiful
It's an old plumb. It's nice. I've actually never set it up to chop yet. One of these days.
@@SkillCult i love plumbs! Thanks for the reply! I hope all is well with you.
You may have had a comment already but force equals mass times acceleration squared. So increase in acceleration squares the force where increase in mass just multiplies it. Its why there is a minimum weight for MLB baseball bats and corked bats are illegal because you gain so much more swinging faster than increasing mass. Also the length of the handle increase angular acceleration given that your arms are swiningat the same speed
yes, that has been brought up. I only understood this principal as a basic concept mostly stemming from practical experience, not mathematically. I was telling my neighbor about what I figured out about wood splitting in my terms and he said "that's the formula for momentum". That's why I drew the formula wrong, because I was only interested that momentum is a product of those two values. But, that there is an efficiency factor between swinging a light v.s. heavy mass is truly interesting. That is super interesting about the baseball bats. Straight theory is one thing, but that's a good practical example. Still, it may not translate entirely in chopping. There you are dealing with a swing speed limitation, whereas in chopping we are not going all out a few times and then quitting, unless maybe in competition chopping. Also, while both bats and axes are impacting, an axe interacts for longer and the energy is absorbed more slowly as the cut progresses the momentum is used up gradually. The target is also usually fairly stationary in its own mass, or fixed to a large mass. So, the question comes up about how a heavy mass interacts v.s. a light mass as the target and axe interact over a longer period of time. I suppose with some controls in geometry and weight you could gain some data, but there are a lot of squirrely variables involved in wood chopping. Again, maximum effort is not necessarily the goal in actual chopping, and the work of swinging a light, v.s. heavy axe is different. And there is practical axe work, v.s. competition, which might be somewhat more analagous to baseball in that it requires shorter bursts of high output. But we know that light axes are not used in competition chopping (at least not that I've ever seen) and that for whatever reasons, heavy axes, to a point, seem to get more work done faster Also, to measure human energy output over the course of chopping a single log, at a similar rate begs a lot of questions. I think some simple tests might give us something to dwell on and things to pay attention to, but trying to prove much unequivocally might be a fools errand in the long run. Thanks for commenting. Good stuff.
Practice will determine the M and V needed for the Kinetic Energy of someone's arrows or axe.
I wish someone would send you a Katanaboy so you can do a competition /efficiency duel between the saw and your axe.Second-Your take on the axes used in Stihl lumberjack competitions(they have massive heads yet chop like crazy)-are they practical?
I don't know much about those axes. I'm sure the katana boy is very efficient. I own and love the silky 180 coarse pruning saw and a long pole pruning saw by them as well. But, they also become dull over time and efficiency drops.
Love it
you focus on the equation for momentum in your past few videos. yes, mass / velocity = momentum, but a person can only add so much velocity, and you can only add a part of that max velocity while maintaining accuracy and being calorie efficient. a slower, rhythmic swing with a heavier axe will typically move more wood than many fast chops with a lighter axe.
you should also look at the equation for general force. Force = Mass x Acceleration. given that earth's own gravity accelerates everything (straight down) at around 32 ft/s/s, heavier axes that are in free-fall impart more force than lighter axes. extra energy (calories) by the user are needed to further accelerate the lighter axe to match an equivalent force. true, you still have to pick up the larger axe and burn some extra calories in doing so, but the width of wider axes reduces the number of chops in most typical logs, and the chip breaking power of heavier, thicker heads also reduces precious calories burned trying to yank a stuck axe out of the scarf!
that said, smaller axes are more efficient at chopping smaller diameter (less than 6"-8") logs, especially if they are above waist height. also, my above rant presumes that the larger axes are ground correctly to be efficient choppers. IMO, lighter axes take less factory grinding to be productive, so the thicker, heavier heads tend to come a little more unfinished to meet a price point that is still acceptable from consumers.
"you can only add a part of that max velocity while maintaining accuracy
and being calorie efficient. a slower, rhythmic swing with a heavier axe
will typically move more wood than many fast chops with a lighter axe."
Maybe, maybe not. I don't know, but try to prove it and I think it will be tough to do so to another person. There is definitely a limit to velocity that makes light axes limited at some point, or if you look at it another way, a heavy axe, if someone can swing it fast, has a higher work potential. If you've proved it satisfactorily to yourself, that's of some value.
Things fall at the same rate, so we are back to making calculations of energy input on lifting and accelerating a light axe v.s. lifting and accelerating a heavy axe to hit with the same force, or more relevant, to do the same work. Calculations that no doubt could be done, but don't take into account a range of human variables in actual use. That's why I said it's hard to prove and probably not worth the effort. It would be interesting for sure, but not at a high cost.
That's the wood chopping philosophy I've always subscribed to slick. I'll take the heavier axe and hatchett with a good sharp edge everytime...the non phisist forgot to include the axe edge into the mathematical equation.
I just wonder what the kinetic energy is. So for a throwing axe I got 28mph when it hit the target. The axe weighed 21000 grains or 3 pounds. That equals 78 foot pounds of kinetic energy. The same as a powerful compound bow. Less than a crossbow though.
Awesome explanatarion. You sure seem like a fysikist to my.
Were you at rabbit stick thirty years ago with Jim Riggs
I"m not sure when my first rabbitstick was. I think it was the second one after they restarted it. I was probably about 22 or 23 maybe, so 33 or 34 years. Jim Riggs was a good friend and teacher of mine.
Thanks I went to rabbit stick for about eight or ten years
@@fredflintstone6163 I was probably there a lot of those times
I thought it is inbuilt
I cannot lie, smart is hot!!!! And the ability to explain it well is . . . AAAAAmazing! Thank you for this video! As I get older, less braun is available so I appreciate the science and math.
Yeah I fall hard for smart girls lol. So far they have not worked out though. They're complicated and quirky.
Dude you are like a sorcerer
A boys axe seems to me to be better on my body if the handle has proper flex. Easier on my arms, wrist hands.
#3-1/2 is the perfect weight for a faller for me. Bites deep enough with an easy swing and I can keep chopping steadily for a long time. Whether DB or SB. I just love axes! Thanks for makin the vids man.
That's definitely heavy for me, but I'm not in very good shape anymore either. I'm also very accustomed to one handed use and the maneuverability of short handles for general diverse axe work. Someday I'll decide what my sweet spot is, but I'm not really in a hurry. Cheers!
SkillCult. I have a 3-1/4 pound KATCO Dayton on a 30" stick that I use for chopping trees once down(if I'm not using a cross-cut saw). Anything under #3 for me feels like I'm wasting energy. I enjoy your videos man!
My brain hurts. May I be excused?
Not quite correct. It is energy at the point of impact. That is 1/2mv^2. That means the faster the axe hits the wood the more energy it imparts in proportion to the square of the velocity. With the same effort, the smaller axe head moves faster. Also the speed is proportional to the square of the haft length. So you need a long handle and a small head. The equation is
E = 1/2(F^2d^2/ 2m).
Let’s compare a 1.2kg axe with a 70cm handle and a 3kg maul with the same handle. The same person wields both. F and d are the same. E1 is the axe and E2 the maul. The we want the ratio of the kinetic energies at the point of impact E1/E2. This is 0.83/0.33 = 2.5. That means that the energy imparted to the log by the smaller axe is 2.5 times the energy from the maul. I use a 800g head on a long handle. Dont know how they get away with selling mauls.
You are wrong. The energy in the axe head is proportional to the square of the velocity. A smaller axe head can be accelerated faster. So a small axe head on a longer shaft gives four times the impact energy than a large head on a shorter haft. The ultimate useless axe is the splitting ng maul. The equations are in a paper I uploaded. Chris Busby. Physicist.
Many have pointed that out, but how does that play out in overall energy expenditure. Is there really a free lunch there? Give a lumberjack chopping down a redwood tree a 2 lb head and a 4 lb head, both on 36 inch handles and he is going to end up using the heavier axe. Is he just stupid? I"m not arguing with the math, just saying that in real world contexts there are more considerations than a simple equation, especially given the complex mechanism of a body, energy and acceleration. Give me a pile of firewood with a maul and a boys axe and I'm going to end up using the maul a lot more, just because I can only accelerate that light axe so fast and then hit a limit.. Just saying there are real world concerns at play, which no one seems to want to talk about Feel free to enlighten me.
Speaking the right language, my friend. #ItsYourFuneral lol
I've been thinking up some good hashtags. I like that one :)
Own it.
Yah, once momentum = 0, there is no sense in pushing more.
The best cutting axe is your skill?
3 x 75 is NOT 100. But energy does causes everything. Also kinetic energy equals half the mass times the velocity squared. KE=(1/2)m*(v^2). So velocity is more important than mass.
100 was arbitrary, just to have a number. Thanks.
thank god somone mentioned the correct definitions.
Directed here by Essential Craftsman, think I'll be here a while
Welcome.
Not that it matters, but you could just as easily (and probably more accurately) utilize; E=MC2
E= Energy (i.e. impact of momentum)
M= Mass (i.e. 'duh')
C= Speed (i.e; Velocity) [,,, and this is as you know squared. x2 speed = x4 'momentum' of mass at impact]
,,, apart from shuffling the factors, this is essentially what you've just deliberated. Just like how you've mentioned before, how bigger/longer swings, (amplified by length of shaft, how well we're exploiting the centrifugal force with body-weight during swing, etc.), allows for more velocity to build up with subsequent results.
Just thought I'd mention it, since Einstein's equation is well known for it's general applicability
Yeah, that's stuff is beyond me, but thanks :)
No no no. E = mc2 is the mass-energy equivalency equation. c is the speed of light in this equation. If you multiply the speed of light squared by the mass of something, you get the amount of energy that mass has simply because it has mass. It has nothing to do with the mass moving. Skillcult was close. It should be mv = p. Mass times velocity equals momentum (p).
Yeah, speed of light (or causality) was an erroneous overkill (being a max by itself, so no x2), but my understanding is that it translates to the roughly the same. If you double the speed, the mass will have an x4 impact, but the amount of energy put in for the added speed of the mass, is accordingly.
Far as I know, E=Mc2 is not limited strictly to the conversion from mass to pure energy (motion is the factor, even if it's less than max), but regardless. I thought it was easier to relate with something as familiar as E=Mc2, even though it goes by the relativistic mechanics of kinetic power, rather than the classical mechanics of mv=p.
I might be somewhat wrong here, but insofar as we're operating with speeds slower than light/causality, mv=p is just a less 'astronomical' equation, ultimately intertwined with E=Mc2.
E=mc^2 is used for calculating the total energy stored in given mass. E=1/2mv^2 is used for calculating kinetic energy.
EmLill Things nope. It's only for calculating energy stored as mass. en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence?wprov=sfti1
Very good - it's not rocket surgery.
Noce.
The chickens got it.
hillbilly physics works..... it is all physics.... lol
Poor living tree
Trust the science
Don't trust anybody or any information. Trusting science is science as religion, which is very un-science -ike. Definitely don't trust my hillbilly science, but take it into account. Information is not knowledge. Knowledge is personal.
@@SkillCult
I was making a joke in regards to something in your video😁
The "science" is like the proverbial foundation of sand Jesus warned of, forever changing at a moments notice, rarely standing up to scrutiny and tribulations (storms), and often subject to those funding the research or those in power
Oooooh. Plumb Permabond!
That thing is old and weathered, but still tight! I wonder what is going on under that epoxy....
My guess is voodoo. Good, ol' fashioned...voodoo.
I've been meaning to get one for ages, but just because the top of the head's welded into the eye with completely weather- and shock-proof...don't mean the rest of the stick is, and so the rest of the handle is often completely RS. And, yeah, you could rehandle 'em...but a) it's not Permabond, obviously, then, and b) good lord, do I want to be scraping 50-year-old epoxy out?
I really should get one though, since Plumb, after all, invented the Tassie Pattern, and the Plumbs are quite cute compared to my Hytests and Keesteels.
I think they were the ones that also used expanding metal wedges? Not sure, but I think so.
The Tassies? Used both, over the years. Take-up wedge early on, then Permabond was post-WWII, like the American axes. If postage wasn't a killer, I'd send you a 4.5lb Hytest to make a vid with.
The Plumb Take-Up Wedges (ah, I love the old timey names for things) were expanding ones. I don't think the wedges themselves expanded - they were just a conical screw with a massive taper, and you turned it to force the wood apart when it shrank.
First, I agree with your overall point here and you are usually spot on. However, be careful with your notation. The way you wrote the equation on the axe, it reads "mass DIVIDED BY velocity equals momentum". I know you meant "mass TIMES velocity equals momentum" because you stated it elsewhere, but the way you wrote it on the axe, as the velocity increases the resulting momentum decreases for a given mass. Obviously that is impossible, and is exactly the opposite of what you meant, but that is what you wrote. I know you are intelligent and do not doubt your actual understanding of axes, but this kind of oversight and inconsistency creates confusion and will erode your credibility with the mathematically/scientifically literate.
Yeah, I'm under edumacated. I don't care though, because the point is that the interplay of mass and velocity together creates the product velocity, which I made clear enough. I'll never use the math and not likely that anyone else will either. It's not very useful in such a complicated scenario as someone swinging an axe.
"Fisicist or Sciencer"
For any given axe man, he can only increase the mass of the axe head. I guy who doesn't have arm speed cannot wish it in to being. He can get a bigger axe providing greater KineticEnergy=1/2*mvEE2 by increasing the mass. But you are right because of the square of velocity in the equation, making it far more of a factor than mass. KE=0.5mvv , this is the equation that explains why velocity is more important. Exponentially more important.
many people have brought up the formula that speed is more of a factor, but no one has addressed the energy inputs involved in generating more speed or generating an equivalent momentum. Isn't that unaccounted for in any of these equations?
rubbish its weight, try swinging a 1 lb hatchet as fast as you can and it will never cut as deep as a 2.5lb axe.
so you've just lost a another viewer with this video
I address that point in the long version by using the rule of extremes, but good riddance.
Rasputin's apprentice The equation for kinetic energy is KE = (0.5xMass) x (velocity squared), so not only is speed way more important than mass, but mass is actually half as important as you think it is.
The reason you’ll cut deeper with a 2.5lb axe over a 1lb hatchet is because a 2.5lb axe will have a way longer handle, and angular velocity (the speed at which you can swing the axe) is equal to the linear velocity multiplied by the radius of the arc (the handle length). Basically, if you had a 2.5lb hatchet and a 2.5lb chopping axe, you’d be able to reach a much higher velocity with the axe, which would impart more kinetic energy to the log.