Tell me about Axes....

[Marshy]

What-the-he!! does that have to do with what we were talkin' about??
He's talkin' about two separate masses, both in motion, powered by the same force, at the same time, and during the same time frame‼

At 3 minutes in, he says energy is the product of force times distance... that's true. But in the case of our billiard balls, the force is applied to only one ball, by the cue stick, and for only a short (very short) distance. As the cue ball glides across the table, there is no force applied to it (or, more correctly, work being done on it)... it is momentum that carries it across the table. The distance (or time) it glides across the table is not part of the equation... period‼

When the cue ball strikes the stationary ball, the force of momentum pushes on the stationary ball for very brief moment in time and/or distance (and the stationary ball pushes back with it's momentum of zero). Now, remember, force is not energy... energy expended (work) is the product of force and distance (which may, or may not be, measured by time), which is equal to the (in this case) kinetic energy (W=Fd=Ek). With the billiard balls, the principle of Conservation of Momentum applies, the momentum of one is transferred to the other, the stationary ball has zero momentum before the collision, but acquires the momentum of the moving ball after... and the moving ball acquires the zero momentum of the other.

So let's go back to the 3 ounce ball moving at 40 FPS striking the stationary 6 ounce ball. If the strike is square, the 6 ounce ball moves away from the collision at (almost) 20 FPS because the force acting (working) on it is the momentum... energy is not force, but momentum is. The kinetic energy that the 6 ounce ball acquires is the product of force (momentum) and distance (or time), the kinetic energy of the moving ball is not part of the equation... period‼ Which is exactly what was stated 3 minutes into your video. And the striking ball?? Well, the force acting (working) on it at the collision was the momentum of the stationary ball (zero momentum)... and the product of zero force and anything equals zero kinetic energy. Also exactly what was stated 3 minutes into your video.

Now I know I said that kinetic energy didn't really exist, but that's not entirely true... I was playing with words to make a point. Kinetic energy is a scalar quantity, not a vector like momentum... kinetic energy has no directional force (it ain't a force at all). And if energy, no matter its form, can not be created nor destroyed, and only half of the energy possessed by the 3 ounce ball was transferred to the 6 ounce ball... where did the other half go?? Well the other part of that physics law is that energy can be converted... the other half of that kinetic energy was converted into several forms, such as sound energy, heat energy at impact, vibration, and whatnot. There ain't any such thing as a truly "closed system" (on this planet anyway)... there will always be loss of energy through conversions, as well as some loss of momentum (or force). That's why I said, "(almost) 20 FPS."

So how does all of this apply to splitting wood??
Well, you can claim all the kinetic energy you want... but the force acting (working) to split the wood is momentum ('cause energy is not force)... there is also, or should be, at least some force from the user at impact.
I can shoot a small steel wedge (or steel core bullet) from a gun at several thousand feet per second, and it would carry an awesome amount of kinetic energy... but it won't split the log.

Enough said.
*

Spidy, your missing a lot of my point and a lot of how momentum and kinetic energy is transfered. Your only considering half of the equation/theory. I agree with your first half of your post up until you try to explain what is happening with the balls colliding. Kinetic energy is comprised of an objects momentum. Momentum is mass x velocity and kenitic energy is 0.5 x mass x velocity squared. You cant predict final velocity of two obkects colliding without considering momentum AND kinetic energy. Its called conservation of linear momentum and elastic collision and it uses both momentum and kinetick ernergy.

A 3 oz ball moving at 40 fps has twice as much kinetic energy as a 6 oz ball moving at 20 fps but their momentum is the same.

If the 3 oz ball moving at 40 fps collides with a 6 oz ball that is 0 fps then the proper approach to finding the final velocity of the balls is to combine conservation of momentum AND conservation of energy. Linear impulse of two objects defines how the objects react. As we both agree, the total amount of momentum is conserved. Thats is, the 6oz ball will travel 13.3 fps in the direction the 3oz ball was traveling in. After colusion, the 3 oz ball will actually travel 6.6 fps in the oposite direction. "The other half" of kinetic energy is not dissipated as heat and noise, those are minor losses that can be ignored and still get accurate predictions on final velocity post collision.

If you'd like to make a post to debate this further we can do that. I'd suggest the political forum where bickering is encouraged.

Please read this before you do though...

http://www.sparknotes.com/physics/linearmomentum/collisions/section1.rhtml#1d

 

[Idahonative]

What-the-he!! does that have to do with what we were talkin' about??
He's talkin' about two separate masses, both in motion, powered by the same force, at the same time, and during the same time frame‼

At 3 minutes in, he says energy is the product of force times distance... that's true. But in the case of our billiard balls, the force is applied to only one ball, by the cue stick, and for only a short (very short) distance. As the cue ball glides across the table, there is no force applied to it (or, more correctly, work being done on it)... it is momentum that carries it across the table. The distance (or time) it glides across the table is not part of the equation... period‼

When the cue ball strikes the stationary ball, the force of momentum pushes on the stationary ball for very brief moment in time and/or distance (and the stationary ball pushes back with it's momentum of zero). Now, remember, force is not energy... energy expended (work) is the product of force and distance (which may, or may not be, measured by time), which is equal to the (in this case) kinetic energy (W=Fd=Ek). With the billiard balls, the principle of Conservation of Momentum applies, the momentum of one is transferred to the other, the stationary ball has zero momentum before the collision, but acquires the momentum of the moving ball after... and the moving ball acquires the zero momentum of the other.

So let's go back to the 3 ounce ball moving at 40 FPS striking the stationary 6 ounce ball. If the strike is square, the 6 ounce ball moves away from the collision at (almost) 20 FPS because the force acting (working) on it is the momentum... energy is not force, but momentum is. The kinetic energy that the 6 ounce ball acquires is the product of force (momentum) and distance (or time), the kinetic energy of the moving ball is not part of the equation... period‼ Which is exactly what was stated 3 minutes into your video. And the striking ball?? Well, the force acting (working) on it at the collision was the momentum of the stationary ball (zero momentum)... and the product of zero force and anything equals zero kinetic energy. Also exactly what was stated 3 minutes into your video.

Now I know I said that kinetic energy didn't really exist, but that's not entirely true... I was playing with words to make a point. Kinetic energy is a scalar quantity, not a vector like momentum... kinetic energy has no directional force (it ain't a force at all). And if energy, no matter its form, can not be created nor destroyed, and only half of the energy possessed by the 3 ounce ball was transferred to the 6 ounce ball... where did the other half go?? Well the other part of that physics law is that energy can be converted... the other half of that kinetic energy was converted into several forms, such as sound energy, heat energy at impact, vibration, and whatnot. There ain't any such thing as a truly "closed system" (on this planet anyway)... there will always be loss of energy through conversions, as well as some loss of momentum (or force). That's why I said, "(almost) 20 FPS."

So how does all of this apply to splitting wood??
Well, you can claim all the kinetic energy you want... but the force acting (working) to split the wood is momentum ('cause energy is not force)... there is also, or should be, at least some force from the user at impact.
I can shoot a small steel wedge (or steel core bullet) from a gun at several thousand feet per second, and it would carry an awesome amount of kinetic energy... but it won't split the log.

Enough said.
*

Spidey, if you could split wood as good as you run your mouth we would all bow down and worship you as THE wood splitting God. But you don't so we won't. The conversation is about axes and wood splitting. No one cares about the boring garbage of which you speak of. Sorry if that sounds unkind

 

[zogger]

Yeah man, thought that would happen. Probably only good for small rounds. Guess you could noodle the bigger stuff then split it with the axe. I like to cut everything then go crazy with splitting though. Having to switch from chainsaw to splitting apparatus.



You're making it sound like the Fiskars will blow through rounds like a hot knife in butter. Hope that's the case. I've hit my shin with the side of a maul before. Didn't feel too great.

I naturally stand feet apart, feels more stable. You lift the axe straight up? I've always swung up it back over right shoulder then straight down.

Ya, that's a heavy maul swing. Not needed with the fiskars plus it is safer/more effective (for me anyway) to do the straight on approach and overhead straight down swing. I looked but couldn't find the official fiskars vid with their spokesmodel splitting that way. too many fiskars vids on utoober now.

 

[Ambull01]

I would say two or three wedges, but I split 10 cords last month and only used the wedges on about 10 rounds, only needed two one time. Probably would have been easier to roll it back up and noodle it, but I had the maul in my hand. It was a 40" diameter bigleaf maple stump round. And I suspect you could substitute an ax for the Fiskars and be just fine. I have a 6 lb maul, a 3 1/2 lb double bit ax and two 2 1/2 lb axes, 3 steel wedges and can split anything I have ever encountered. I will probably get a Fiskars to try eventually, I am intrigued.

Yes, ergonomically, it expends less energy to thrust the maul straight up, then start it down. If you are using a maul or sledge on a wedge, if you get bounce and can translate the momentum into a big roundhouse, then it can make sense to let the hammering device get behind the vertical plane. Wish I could remember where I saw the study.

So much arguing...

I definitely need more than one wedge. I've had two wedges stuck in a round before. Had to flip it over and beat the crap out of it to get the wedges out. Another wedge would have come in handy.

What do you use the double bit axes for?

Hmm, I have to test that swing. It seems like it would be harder to lift the maul/axe straight and over your head since your hands would probably have to hold the handle at the end vs sliding your top hand up the handle as you would with the over shoulder strike. How do people swing those large carnival sledges when they try to hit the bell?

 

[Ambull01]

Ya, that's a heavy maul swing. Not needed with the fiskars plus it is safer/more effective (for me anyway) to do the straight on approach and overhead straight down swing. I looked but couldn't find the official fiskars vid with their spokesmodel splitting that way. too many fiskars vids on utoober now.

Okay I think I get it now. The Fiskars is wood's kryptonite. Swinging it predominately up and down lessens the chance of hitting the round at an angle or misjudging the strike which would make it kryptonite to the person holding said axe. I'll look for the video.

 

[BeatCJ]

What do you use the double bit axes for?

Splitting, limbing, popping rounds that don't get cut all the way, cutting brush, whatever. Just another tool, but it's heavier than my single bit axes.

Hmm, I have to test that swing. It seems like it would be harder to lift the maul/axe straight and over your head since your hands would probably have to hold the handle at the end vs sliding your top hand up the handle as you would with the over shoulder strike. How do people swing those large carnival sledges when they try to hit the bell?

Actually, you slide the handle through your upper hand, just do it with the handle pointed straight up.

 

[zogger]

Looks great. Did you see the video of that guy splitting a mass of rounds with a rope or something around it? Raced against the clock. I have to look for it again.

There's one from an old member here doing a lot in a short time with the rope or bungee cord trick.



and here is a fiskars in good wood speed demo

 

[Ambull01]

Splitting, limbing, popping rounds that don't get cut all the way, cutting brush, whatever. Just another tool, but it's heavier than my single bit axes.
Actually, you slide the handle through your upper hand, just do it with the handle pointed straight up.

lol. Sorry, I'm over thinking this way too much. Just hit the freaking log Ambull!

I was thinking you guys meant lift the axe straight up. That would be a little difficult to do while sliding your hand forward. If you lift it slightly above your left or right trapezius muscle then it sounds doable. Anyway, I'll shut up now.

 

[Ambull01]

There's one from an old member here doing a lot in a short time with the rope or bungee cord trick.



and here is a fiskars in good wood speed demo

The second video is the one I mentioned! Thanks

 

[Whitespider]

BU!!$HIT Chris-PA,
Mechanical energy (which can be kinetic) enables an object to apply a force to another object.
Mechanical energy (which can be kinetic) enables an object to do work, through the application of a force.
Mechanical energy (which can be kinetic) does not drive the nail, the force of momentum does (there is a bit of force from the user at impact).
Kinetic energy is a scalar quantity only.
Quoting from your post...
"The mechanical energy of a hammer gives the hammer its ability to apply a force to a nail..."

The energy does not drive the nail. I could swing a ¼ gram hammer with all the energy I could muster, with both arms, until I was too tired to even lift the damn thing, and it still wouldn't have driven the nail... because energy does not equal force.
I ain't the one making up rules here.


Marshy,
You keep going back to elastic/inelastic collisions... and of two "moving" masses, particles no less. In an elastic collision the total kinetic energy of the two objects is conserved, in a perfectly inelastic collision the two objects stick together and the maximum amount of kinetic energy is lost (or converted), in a partially inelastic collision only some of the kinetic energy is lost (or converted).... but in all three collisions the total momentum is conserved.
The collision of two 6 ounce billiard balls is an elastic collision (or as close as we can get to it in the real world).
The collision of the 3 ounce and 6 ounce billiard balls is a (partially) inelastic collision.
And I quote from your link...
"Inelastic Collisions
So what if energy is not conserved? Our knowledge of such situations is more limited, since we no longer know what the kinetic energy is after the collision. However, even though kinetic energy is not conserved, momentum will always be conserved. This allows us to make some statements about inelastic collisions. Specifically, if we are given the masses of the particles, both initial velocities and one final velocity we can calculate the final velocity of the last particle...
In studying one-dimensional collisions we are essentially applying the principle of conservation of momentum."

I just can't see how it can be more plain than that... it is flat impossible to end up with more momentum than you started with‼
*

 

[Chris-PA]

because energy does not equal force.

I never said that it did. I clearly wrote that force = work/distance, and that this is approximately equivalent to KE/distance. It was an equation, it is not something open to interpretation, and is obviously not the same as writing force = KE.

Note that distance in the above statement distance is really supposed to be displacement, which is a vector and supplies the direction. I did this because distance is the magnitude of the displacement vector and it is clear that the force is applied perpendicular to the wood block, but then things get complicated by the shape of the splitting tool head and how the force is directed into splitting the wood - all of which is irrelevant to the fact that the energy to drive those forces comes from your muscles, and can be measured precisely by the mass and the square of the velocity of the tool at impact.

The conversation is silly - no one else is really interested, you are mixing up and mis-using terms and cannot even accept basic principles of physics that have been worked out for some several hundred years. I'm out.

 

[Ambull01]

The conversation is silly - no one else is really interested.

Amen Chris. Amen.

 

[Whitespider]

force = work/distance, and that this is approximately equivalent to KE/distance.

That is totally incorrect... ya' better recheck Newton's second law of motion.
Force is the product of mass and acceleration (f=ma).

Potential energy = force x distance (well, sort'a, it would be height, not distance, for gravitational potential energy... and you still need the gravitational field strength of earth in the calculation)... so potential energy/distance (sort'a) gives us an expression for the expected force (but that ain't the calculation... you need more, which depends on the type of potential energy).
But kinetic energy and potential energy are two different things... a object possesses kinetic energy due to its motion, an object possesses potential energy because of its position, such as gravitational (a ball on top of a ramp), or elastic (a stretched rubber band), or electric (a charged battery).

*

 

[Idahonative]

I beg you people...PLEASE STOP FEEDING THE SPIDER!!!

 

[Marshy]

Spidy, do you have formal education (i.e. a degree)?

 

[mn woodcutter]

There's one from an old member here doing a lot in a short time with the rope or bungee cord trick.



and here is a fiskars in good wood speed demo

I would use a fiskars all the time too if my firewood was like that. Is that some kind of pine? My 12 yr old daughter could split that wood. Much of the wood I split is not conducive to using a light weight fiskars. I'm not saying it doesn't have its place but so many people on here consider it "the end all say all".

 

[Marshy]

I would use a fiskars all the time too if my firewood was like that. Is that some kind of pine? My 12 yr old daughter could split that wood. Much of the wood I split is not conducive to using a light weight fiskars. I'm not saying it doesn't have its place but so many people on here consider it "the end all say all".

I split 6-7 full cord of wood per year with a Fiskar for the past 2 years. All of it is hardwood. Elm, hard maple, black cherry, soft maple and probably others. I've used it in oak, course that pops like a balloon anyways... works fine untill you start getting into wood >24". All of my wood is 18-20" length, green or seasoned. My heavy maul has no handle anymore, its just one more wedge to pound with the sledge when the Fiskar fails to split it...

 

[mn woodcutter]

I split 6-7 full cord of wood per year with a Fiskar for the past 2 years. All of it is hardwood. Elm, hard maple, black cherry, soft maple and probably others. I've used it in oak, course that pops like a balloon anyways... works fine untill you start getting into wood >24". All of my wood is 18-20" length, green or seasoned. My heavy maul has no handle anymore, its just one more wedge to pound with the sledge when the Fiskar fails to split it...

I split about the same amount and maybe more but I haven't had my X27 for all that long. It just doesn't seem to bust up the rounds like my old 8 lb maul did. Who knows, maybe it will grow on me especially now with the addition of the hydraulic splitter I can use the fiskars on the straight grained "easy" stuff. I guess I was surprised at how unimpressive it was considering all the hype it gets.

 

[zogger]

I would use a fiskars all the time too if my firewood was like that. Is that some kind of pine? My 12 yr old daughter could split that wood. Much of the wood I split is not conducive to using a light weight fiskars. I'm not saying it doesn't have its place but so many people on here consider it "the end all say all".

I don't think anyone has said that. What's been stated by a lot of guys is in their wood, they can get a lot done without resorting to a heavier maul, etc. I know I have stated many times I have multiple tools and use all of them. I have posted pics of them. In any wood that is straight grained and splits easy, you can rip it up with a fiskars, or other lighter weight axe, something that isn't an 8lb maul..

As to the guys splitting, they split what is in their locale, what they burn. It's the demonstration of both the rope/bungee trick and actually how fast you can go in *good wood*.

Approximately 1/3rd of my eastern mixed species wood is easy, 1/3 starts to suck but is still doable with the fiskars, then the rest is a crapshoot. Some defies even sledge and wedge and needs to be noodled. Some, half the round is easy splitting, but on the other side it isn't, etc.

It's like saws, no one saw is gonna do all jobs all the time.

 

[Whitespider]

Spidy, do you have formal education (i.e. a degree)?

Nope... dropped out during the 10th grade.
Why do you ask??
*