Speed Vs Power

[PhotonGuy4]

You are not wrong as far as the formula's go, but your argument is illogical and doesn't hold water.
Using velocity as the major contributor for inflicting damage makes sense when you are talking about something like a bullet, which is hard enough to take the impact without major deformation (at least initially) and will maintain nearly all of it's mass intact.

Alright then I stand corrected. Although as Fungus pointed out in post #131 the hand is not cut off from the rest of the body. When you throw a hand strike or a kick your hand or foot stays attached to your arm or leg which stays attached to the rest of your body the whole time. It's not like a bullet which does not stay attached to the gun once it leaves the muzzle, so the physics is a bit different.

When talking about a punch with the hand, or really any kind of strike, the area of the striking component GREATLY changes the dynamics, along with velocity and strength of the striking member.

So, arguing from a basis of kinetic energy or momentum sounds like something a teacher or someone else who has little to no real world concept of how to apply the formula would approach it.
I see this all the time in engineering interns that we bring in as part of their graduate classes. They know the math but don't have a clue how to use it.

Well I did take physics in high school and college but Im still an amateur in that department, I do find it fascinating though and I like to learn.

To answer your question, it is potato/potatoe to me and quite irrelevant. To determine damage, look at the impact area.

Im Im correct impact area has to do with pressure, the equation for pressure is force over surface area so the smaller the impact area the more pressure. That's why striking with the cutting edge of a sword will do much more damage than striking with the flat of the blade, its the same force but applied over a much smaller impact area.

 

[PhotonGuy4]

As HighKick said, the first or the limbs are not rigid bodies undergoing free motion. They are attached, driven and linked to the rest of the body, and the drive through the target is an impulse made up by an integral, you integrate the force over the contact time, and contact distance as it penetrates the target. And unlike a bullet, which has "initial energy", the rest of the body keeps driving the fist throught that target - against resistance - efter after initial impact.

This is why "effective mass" which is when you apply the naive formulate to the complex case is HIGLHY variable, in principle it can vary from "bare limb mass" to your whole body mass, depending on if you use the drive and linking correctly or not.

So while speed and acceleration of hte limb is important, the other things likely makes just as big if not bigger difference. Ie. we have linear dependence on mass, and quadratic on velocity - but both are variable and the choice is not 30% increase in V, vs 30% increase in effective mass. The effective mass can vary alot more.

You sound like you've got quite a background in physics. Might I ask exactly what your background in physics is? I've learned some physics but I never got that far beyond the basics. You talk about other factors such as acceleration and that is an important factor too although acceleration itself can change and that can get really complicated. When you start talking about such stuff I believe it's the more advanced physics that you would have to start using, physics that uses calculus which is beyond the level of physics that I've learned.

Both matters. To break something, you need to both generate sufficient force to overcome material strength but you also need enough energy to complete the breaking. Breaking a rib takes both a certain minimum force, and alot of energy. They key is often to maintain the "drive" throughout the hwole strike. and not "loose force" after 1cm, you need to "drive" the strike through the target until it breaks.

Ontop of this there is also a distintion between inflicting pain(or temporary bruise) and damage (ie breaking/damage opponent).

Yes I've been taught to drive my strikes through the target, in essence not to strike at the target but to strike through the target, although you want your strike to be just that, a strike and not a push.

Anyway I just want to point out, how in post #131 you talk about how when you engage more of your body into a technique you're putting more mass behind it, well putting more of your body into it can actually increase the maximum speed of your hand or foot in terms of MPH because you're adding the speed of rest of your body to the technique.

For instance, when you throw a rear hand straight punch you rotate your hips and body into the punch, therefore the rotational speed of your hips and body is added to the speed of your hand. When you throw a lead hand jab its just the speed of your hand that comes into play since you're not rotating your body into it the way you are with the rear hand punch so with a lead hand jab its just the speed of your hand without the rotational speed of your body added in.

 

[PhotonGuy4]

let it go, let it go
don't argue back any more
let it go, let it go
reading is something of a chore
There's nothing more to say
But the thread goes on
The debate never bothered me anyway

Im not arguing Im learning.

 

[HighKick1]

You sound like you've got quite a background in physics. Might I ask exactly what your background in physics is? I've learned some physics but I never got that far beyond the basics. You talk about other factors such as acceleration and that is an important factor too although acceleration itself can change and that can get really complicated. When you start talking about such stuff I believe it's the more advanced physics that you would have to start using, physics that uses calculus which is beyond the level of physics that I've learned.

Yes I've been taught to drive my strikes through the target, in essence not to strike at the target but to strike through the target, although you want your strike to be just that, a strike and not a push.

Anyway I just want to point out, how in post #131 you talk about how when you engage more of your body into a technique you're putting more mass behind it, well putting more of your body into it can actually increase the maximum speed of your hand or foot in terms of MPH because you're adding the speed of rest of your body to the technique.

For instance, when you throw a rear hand straight punch you rotate your hips and body into the punch, therefore the rotational speed of your hips and body is added to the speed of your hand. When you throw a lead hand jab its just the speed of your hand that comes into play since you're not rotating your body into it the way you are with the rear hand punch so with a lead hand jab its just the speed of your hand without the rotational speed of your body added in.

I am an EE with two mater degrees and a bunch of other certifications (big whoop). My life work and business is in control and automation so physics, statistics/dynamics and yes, calculus is a Big part of what we do. Things like curve loading, projectile motion, stress failure, annd interpolated motion all use calculus.

 

[Fungus94]

You sound like you've got quite a background in physics. Might I ask exactly what your background in physics is? I've learned some physics but I never got that far beyond the basics. You talk about other factors such as acceleration and that is an important factor too although acceleration itself can change and that can get really complicated. When you start talking about such stuff I believe it's the more advanced physics that you would have to start using, physics that uses calculus which is beyond the level of physics that I've learned.

Yes you definitely need concepts from calculus to compute the total impulse transferred when the contact force is variable. Though calculus per see, is also basics even for a physicist. As physics uses the langauge of mathematics, it's hard to get it without math basics such as calculus and some linear algebra.

My main area is theoretical physics and my own favourite area is the foundations of the interactions, such as quantum mechanics and relativity. Basically to seek deeper understanding of why the laws of nature are what they are, and how they were unified at the big bang, mainly from an information theoretic perspective of inference.

Yes I've been taught to drive my strikes through the target, in essence not to strike at the target but to strike through the target, although you want your strike to be just that, a strike and not a push.

Yes, a "push" would have very LOW peak force, and can MOVE the subject by not damage it. So ideall you need both high force and maintain it trough the target. So both concepts matters.

Anyway I just want to point out, how in post #131 you talk about how when you engage more of your body into a technique you're putting more mass behind it, well putting more of your body into it can actually increase the maximum speed of your hand or foot in terms of MPH because you're adding the speed of rest of your body to the technique.

For instance, when you throw a rear hand straight punch you rotate your hips and body into the punch, therefore the rotational speed of your hips and body is added to the speed of your hand. When you throw a lead hand jab its just the speed of your hand that comes into play since you're not rotating your body into it the way you are with the rear hand punch so with a lead hand jab its just the speed of your hand without the rotational speed of your body added in.

True, high speed and high energy are not in contraditiction. A good technique gives a good amount of both, but with a poor technique you can get one without the other. You need to think about both and balance the technqiue. In principle differnt target require different balance. Typically to break brittle brick, you may need high force, but not very much energy. But to break something that is not brittle but deforms, you may need more energy by maybe less force, and more drive. To break a brittle concrete brick does not required much contact time, as once the peak force is there it just cracks. To drive through someones ribs would need much more drive.

 

[HighKick1]

Yes you definitely need concepts from calculus to compute the total impulse transferred when the contact force is variable. Though calculus per see, is also basics even for a physicist. As physics uses the langauge of mathematics, it's hard to get it without math basics such as calculus and some linear algebra.

My main area is theoretical physics and my own favourite area is the foundations of the interactions, such as quantum mechanics and relativity. Basically to seek deeper understanding of why the laws of nature are what they are, and how they were unified at the big bang, mainly from an information theoretic perspective of inference.


Yes, a "push" would have very LOW peak force, and can MOVE the subject by not damage it. So ideall you need both high force and maintain it trough the target. So both concepts matters.


True, high speed and high energy are not in contraditiction. A good technique gives a good amount of both, but with a poor technique you can get one without the other. You need to think about both and balance the technqiue. In principle differnt target require different balance. Typically to break brittle brick, you may need high force, but not very much energy. But to break something that is not brittle but deforms, you may need more energy by maybe less force, and more drive. To break a brittle concrete brick does not required much contact time, as once the peak force is there it just cracks. To drive through someones ribs would need much more drive.

I get what you mean by ‘drive’ but prefer the word ‘penetration’.

 

[Fungus94]

I get what you mean by ‘drive’ but prefer the word ‘penetration’.

Makes sense, english isn't my native tounge.
'penetration' happens to gives me different associations though

 

[PhotonGuy4]

I am an EE with two mater degrees and a bunch of other certifications (big whoop). My life work and business is in control and automation so physics, statistics/dynamics and yes, calculus is a Big part of what we do. Things like curve loading, projectile motion, stress failure, annd interpolated motion all use calculus.

Yes I know, you already mentioned your background in physics in this other thread, I was asking Fungus what his background is.

 

[HighKick1]

Yes I know, you already mentioned your background in physics in this other thread, I was asking Fungus what his background is.

My bad.

How about enlightening us with your background?

 

[PhotonGuy4]

Yes you definitely need concepts from calculus to compute the total impulse transferred when the contact force is variable. Though calculus per see, is also basics even for a physicist. As physics uses the langauge of mathematics, it's hard to get it without math basics such as calculus and some linear algebra.

The physics that I learned used lots of algebra but not any calculus as it was not advanced enough, it was just basic physics. I would still love to learn calculus and the more advanced physics sometime.

My main area is theoretical physics and my own favourite area is the foundations of the interactions, such as quantum mechanics and relativity. Basically to seek deeper understanding of why the laws of nature are what they are, and how they were unified at the big bang, mainly from an information theoretic perspective of inference.

Don't take this the wrong way but you remind me a bit of Sheldon Cooper with the stuff you said. Im not saying you're like Sheldon Cooper personality wise but he is a theoretical physicist and knows all about the sort of stuff you mentioned.

Yes, a "push" would have very LOW peak force, and can MOVE the subject by not damage it. So ideall you need both high force and maintain it trough the target. So both concepts matters.

Well that's why you want speed in your strikes, when a strike lacks speed it becomes less of a strike and more of a push and you don't want that if you want effective strikes.

True, high speed and high energy are not in contraditiction. A good technique gives a good amount of both, but with a poor technique you can get one without the other. You need to think about both and balance the technqiue. In principle differnt target require different balance. Typically to break brittle brick, you may need high force, but not very much energy. But to break something that is not brittle but deforms, you may need more energy by maybe less force, and more drive. To break a brittle concrete brick does not required much contact time, as once the peak force is there it just cracks. To drive through someones ribs would need much more drive.

Even so, when breaking objects such as bricks, boards, ect. we've been taught to drive our strikes through the object not at the object. The same principle applies with other targets such as kicking shields. A kicking shield is a good example of something that is not brittle but that deforms, and we are taught the same thing, you want your strike to go through the kicking shield not at it.

Also concerning force, I think pressure is a better way to look at it. Pressure is force over surface area so when they talk about pounds of pressure what they mean is pounds of pressure per square inch, if you were to take 100 pounds and apply it to an area of one square inch that would be 100 pounds of pressure per square inch.

 

[PhotonGuy4]

My bad.

How about enlightening us with your background?

As I said in post #141 I studied physics in high school and college but it was never my major and while I understand some basic principles I am still very much an amateur. I never learned calculus or the more advanced physics that uses it.

 

[Fungus94]

The physics that I learned used lots of algebra but not any calculus as it was not advanced enough, it was just basic physics. I would still love to learn calculus and the more advanced physics sometime.

Calculus comes naturally and intuitively when you try to study time dependent phenomena and dynamics not not just static physics. ie if you want to understand how a physical quantity Q say change (ΔQ) in a small time step (Δt) you get "differentials", and from there the step to derivatives dQ/dt = ΔQ/Δt as Δt ->0, integrals and differential equations gets natural as the steps are made smaller and smaller Δt ->0.

Don't take this the wrong way but you remind me a bit of Sheldon Cooper with the stuff you said. Im not saying you're like Sheldon Cooper personality wise but he is a theoretical physicist and knows all about the sort of stuff you mentioned.

Both Sheldon as well as the series "Young sheldon" are just hilarious and epic!

 

[HighKick1]

Calculus comes naturally and intuitively when you try to study time dependent phenomena and dynamics not not just static physics. ie if you want to understand how a physical quantity Q say change (ΔQ) in a small time step (Δt) you get "differentials", and from there the step to derivatives dQ/dt = ΔQ/Δt as Δt ->0, integrals and differential equations gets natural as the steps are made smaller and smaller Δt ->0.

Both Sheldon as well as the series "Young sheldon" are just hilarious and epic!

I have to use calculus, a lot, but absolutely avoid it as much as possible. I know it well but pretty much hate it.
We have to interpolate multiple axis of motion quite often and use ∆t and ∆v all the time. I get complex derivation and integration are a shorter formula via calculus but if you ever have to troubleshoot a complex system with a ton of calculus, it can drive you crazy.
Sometimes you just can't get away from calculus, but there is a Lot you can do algebraically with a few extra lines of math.

 

[Prince_Alarming102]

I get what you mean by ‘drive’ but prefer the word ‘penetration’.

The Iggy Pop song, right?

 

[PhotonGuy4]

So since we're talking about speed in this thread I would like to bring this up. I would think that a taller person with longer arms and legs would be able to reach higher maximum speeds with their hands and feet when throwing strikes and kicks in the martial arts. The reason for this is the same reason as to why, when you swing a stick, the longer the stick the faster it will go because it has to cover more distance in the same amount of time.

An excellent example of this would be when you swing golf clubs. The longer the club is the faster the head will go because it has to cover more distance in the same amount of time. The head of a 3-iron will go faster than the head of a 9-iron. Why? Because the 3-iron is a longer club. By the same concept, when a taller person throws a punch or kick, their hand or foot will be going faster than that of a shorter person. A taller person vs a shorter person punching and kicking would be like swinging a 3-iron vs swinging a 9-iron.

 

[Fungus94]

the longer the stick the faster it will go because it has to cover more distance in the same amount of time.

This assumption will not hold in reality. Your assumption implies that more energy and power power is also available to set the longer and heavier stick into same angular velocity. But if the muscles or power of the engine at hand is the same, just making the stick longer will cause hte longer stick to move a slower angular rate due to limiting power behind.

So explanation would be more complex

when a taller person throws a punch or kick, their hand or foot will be going faster than that of a shorter person.

You would then also need to assume that the taller person has more power (bigger muscles), otherwise this will not hold true.

But often a bigger, taller and heavier person may also have more muscles, but this is not always the case, and the height per see, or limb lenght per see, does not automatically make the punches faster if your muscles are limiting factor.

example: if you gear up your moped (tiny engine) with a higher gear, you might be able to increase top speed until air resistance is limiting, but acceleration will be slow. your example above is assuming the acceleration is the same, even if you gear up, which is not the case unles the engine is also beefed up (pull the plug out of the inlet of the carburetor for example).

 

[HighKick1]

This assumption will not hold in reality. Your assumption implies that more energy and power power is also available to set the longer and heavier stick into same angular velocity. But if the muscles or power of the engine at hand is the same, just making the stick longer will cause hte longer stick to move a slower angular rate due to limiting power behind.

So explanation would be more complex

You would then also need to assume that the taller person has more power (bigger muscles), otherwise this will not hold true.

But often a bigger, taller and heavier person may also have more muscles, but this is not always the case, and the height per see, or limb lenght per see, does not automatically make the punches faster if your muscles are limiting factor.

example: if you gear up your moped (tiny engine) with a higher gear, you might be able to increase top speed until air resistance is limiting, but acceleration will be slow. your example above is assuming the acceleration is the same, even if you gear up, which is not the case unles the engine is also beefed up (pull the plug out of the inlet of the carburetor for example).

You are 100% correct as long as the moving items are not able to reach terminal velocity. An (attached) arm or leg never get anywhere close to TV.

 

[PhotonGuy4]

This assumption will not hold in reality. Your assumption implies that more energy and power power is also available to set the longer and heavier stick into same angular velocity. But if the muscles or power of the engine at hand is the same, just making the stick longer will cause hte longer stick to move a slower angular rate due to limiting power behind.

I see what you mean but what about with golf clubs? The longer clubs are designed to hit the ball further and they're made longer for that reason, a faster head speed means your golf ball will fly further.

 

[PhotonGuy4]

Both Sheldon as well as the series "Young sheldon" are just hilarious and epic!

Well in post #145 in the same paragraph where you mention theoretical physics being your main area you also say "big bang," made me think of Sheldon Cooper right away. Im sure you're more physical than Sheldon though, being in a martial arts forum and all.

 

[Fungus94]

I see what you mean but what about with golf clubs? The longer clubs are designed to hit the ball further and they're made longer for that reason, a faster head speed means your golf ball will fly further.

I'm not a golfer but I while think its more than lenght (different angles of the clubface, different materials and weight) but apart from that, the principle of longer clubs is no different than "higher gear". It does work, but only if you have enough strenght or torque to reach as similar end angular velocity or rpm.

So longer clubs, or higher gears, longer limbs, may get you higher end speed, but only until the limiting factor is the torque, or muscle strength.

With a given engine power, higher gears offer potential higher top speed, but slower acceleration so there is still a balance required. So if you upgrade your gearbox, you should also upgrade the engine, and your tires etc.

so just growing long limbs alone, is not going to be good.