# Force generation

Discussion in 'General Science & Technology' started by IndianCurry2010, May 10, 2011.

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1. ### IndianCurry2010Registered Senior Member

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Guys,

Its mainstream and known by everyone that Force = Max x Acceleration.

My question is this only applies in a straight line. So if a boxer strikes an opponent the maxim power will be exerted on a straight punch now a hook as there will energy leakage is this correct ?. I guess it must be true if a bullet swerved it would loose penetration power right ?

3. ### fedr8081100101Valued Senior Member

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what?

I have no clue what the context of this is. And very little clue of what the actual question is.

5. ### IndianCurry2010Registered Senior Member

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87
Apologies if I havent explained myself correctly. If a boxer does straight punch it will be more powerful then a round house or hook punch. As he has to circle to do the punches. Whereas a straight punch is straight out in a straight line is this correct thus no leakage of energy right ?

7. ### Me-Ki-GalBannedBanned

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I don't know , never learn that shit , but there is something to be said about the force of a pendulum where as one point is anchored to a stationary position , Centrifugal forces

8. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Mass x acceleration.

Huh? Why do you think this?

There is no similarity between these two cases. A thrown punch may well be under acceleration until it actually connects. A bullet ceases accelerating shortly after it leaves the gun barrel. The force is applied to get it moving in the first place: after that it's losing velocity (decelerating) all the time.

Not necessarily. By taking a longer route a punch may well be accelerated more (i.e. more force) than a straight punch taking a shorter route (less time to provide the impulse).
For example when I took kick-boxing lessons we were warned that a hooked kick had been known to break pelvises (even in practice at less than full power) whereas no-one had ever heard of it being done with a straight kick.

9. ### IndianCurry2010Registered Senior Member

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87
OK the reason why I asking this is watch the following video of a famous boxer he talks about how a punch should be in a straight line and if it curves energy leaks..

He says the fist should be recoiled in a straight line and moved out in straight line to create impact what do you think guys ffrom a science perspective ?

10. ### fedr8081100101Valued Senior Member

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As someone that has done both and then some the hook punch is far more powerful TYPICALLY.

The reason is because a punch is not as simple as you'd think. A weak punch is one where all you do is extend your arm and hit them.

A strong punch is where you rotate the balls of your feet. So if you have your right leg back in a fighting stance and you punch with your right fist forwards then you also rotate your ankles counterclockwise which rotates your entire body into the punch.

Now, the reason why a hook punch is more powerful is simply because you can rotate your body further. Most people think a hook punch means moving your biceps until you hit the bad guy, its not. You have your biceps almost parallel to your shoulders, and your arm is ninety degrees from your biceps, you rotate your entire body and only ever move your actual arm when your fist is maybe a foot or two away from the opponent and then you finally extend the fist mid rotation until it makes contact.

A hook punch to say it simply has more force behind it then a normal punch because you rotate your entire body behind it further then you would rotate with a normal punch.

A normal punch can have you rotate about 45 ish degrees, a hook will have you rotate closer to 90.

That extra distance means more time to accelerate, more acceleration means more speed at impact, and more speed at impact means more force.

There are a few reasons why you shouldn't do a hook punch.

1. If someone has actual training then they know not only how to block the hook punch (which is easy) but how to promptly beat the crap out of you, throw in a few punches, kick you in the balls, and then throw in some knees for good measure before you can even retract your arm.

2. The only target you can really rely on is your opponents head. Which is just about the single worst place to try and punch someone. If your fist is a truck, then their head is a tank. And while you may deal some damage, their skull will deal similar damage back on your hand, and between the two guess which one is likely to hurt worse after it.

If you have to hit someone in the head, hit them with an open palm, if you rotate into it you can put a hell of a lot of force into it.

My rule of them is this.

Anything from the feet to the abdomen is a target for a front kick or knees.

Anything from the balls to the abdomen is a target for punches.

Anything from the abdomen to the ribs is a target for a side kick (Namely because a good sidekick involves leaning backwards so it raises your foot upwards)

Anything from the ribs to the face is a target for open palm strikes.

And just about anything except for the top of the skull is a target for hammer fists.

11. ### fedr8081100101Valued Senior Member

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It's true... to a degree. But keep in mind this guy beats the crap out of other people for a living. So it is reasonable to say he is not a physicist.

Energy leaks is BS. But the second part of your post about recoiling the fist upon impact is true.

12. ### jmpetValued Senior Member

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1,891
Why is the punch curved in the first place? To hit a weak(er) spot. A lot of the physics of this applies here as well.

13. ### IndianCurry2010Registered Senior Member

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Fed why do you say the energy leakage is BS please can you elaborate on this ?

Thanks

14. ### IndianCurry2010Registered Senior Member

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87
It might be worth me applying his method on a punch bag and see if there is an energy leakage god knows how you measure energy leakages

15. ### Me-Ki-GalBannedBanned

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That is a particular style of fighting . You need to explore other methodology . There was a boxer that was very successful at the straight line punch . I forget his name . Foreman maybe ? can't remember ? He had very long arms from what I remember and could generate a lot of force by his method of foot work staying at the maximum distance to make good contact . No one expected it an it was almost like a sucker punch for the ones that got hit by it were suckers for the punch . Very effective for the fighter in the day . That is all blawzay now a day. You want to be a good fighter learn grappling moves . They may not be as flashy but the effectiveness is out of this world magic stupid like . Put the Hurt On !!!

16. ### billvonValued Senior Member

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There are no energy "leaks" from something moving in a curved path. Look at any pendulum. There are just differences in how the mass is accelerated and deflected.

17. ### fedr8081100101Valued Senior Member

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Well first off, if there is energy "leakage" where is it "leaking" to?

18. ### Stoniphiobscurely fossiliferousValued Senior Member

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Wow. Pretty silly, guys.

The energy delivered to the target by a straight punch involves linear velocity (M*V squared), the energy delivered to the target by a curved punch involves what we call angular velocity - (M*omega squared). Angular velocity quickly acquires much more momentum than linear and can cause much more damage (deliver much more kinetic energy) to the target. Yes, a pendulums' motion involves angular velocity, not linear velocity.

The single most devastating punch a fighter can deliver is termed a "spinning back fist". You "set up" your opponent with a "straight jab" with your lessor hand (the left of you are right - handed) to the chin, then spin 360 degrees to strike him in the head with the top of your strong fist (the right if you are right - handed). The target of choice is the point where the jaws meet. That provides a pretty much guaranteed knock - out. Everyone that I have every seen receive a spinning back fist has gone down immediately and not gotten back up.

A "sucker punch" is a punch that is intended to suck a fool into fighting with you. You reach out unexpectedly and tap the opponent on the chin, causing no damage. You have, however, provided him with the basis for a "self defense" excuse for hitting you back...if he is able to do that. "He hit me first."

That is why we call it a "sucker punch". If you try to defend yourself using that as an excuse, you will most likely get thrashed pretty badly, as only a very confident street fighter will give you that move.

The last time someone tried a sucker punch on me I grabbed his pinkie finger when his hand was in my face and immediately dislocated it. End of fight attempt.

If you receive a "hook" punch to the jaw meet, you will very likely be knocked out (rendered unconscious).

19. ### fedr8081100101Valued Senior Member

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Obviously you have never actually put this into practice. For starters a spinning punch only works if your opponent is a complete freaking moron. You know how easy I mentioned that it was to block a hook? I could block a spinning back fist in my sleep. Next thing your gonna tell us is that the super man punch is actually a good idea

A jab is a straight linear blow. A punch is not, there is a lot more rotation in a punch then what you seem to believe.

ya, you'll be knocked unconscious with that hook punch, but you will have the satisfaction of knowing that chances are you broke most of the bones in the opponents dominant wrist. And if somehow you aren't knocked out then you have won. There is no way your opponent can wield a broken wrist as a weapon. That's why you never actually do those silly attacks. Because breaking your wrist can easily make you lose a fight.

Why do you think boxers wear gloves? Or there is such a thing as brass knuckles? Because those weapons keep the fragile little bones in your wrist from breaking apart.

20. ### Stoniphiobscurely fossiliferousValued Senior Member

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Pretty funny, and very speculative, young fellow! :bugeye:

Maybe my Taekwon Do, Kronk boxing and kickboxing instructors were all wrong after all. :shrug: Maybe my many years in the ring and as a PKA kickboxing judge were folly, error and wasted time. Perhaps all of the students I have given instruction to over the years have been severely mislead.

Conversely, maybe you have no actual training in ring fighting or MA techniques. I strongly advise you to get some serious instruction before attempting to use your 'wisdom' in a real world altercation. Otherwise you are in for a rather nasty - and painful - surprise.

The are some good tv shows on martial arts and ring/octagon fighting that you should consider viewing. You may well become enlightened.

21. ### fedr8081100101Valued Senior Member

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Consider krav maga. Do you actually think real fights are one v. one? Or that there's a cute little ring? Or that there is a referee to keep your opponent from bashing your brains out?

I am a black belt in tae kwan do and I can tell you that it is absolute crud. The most useful thing you can learn is side kicks, which I'm not gonna lie is one of the handiest self defense moves you can have. But those forms you do, the techniques, utterly useless in a real fight.

A swinging back fist is utterly useless. You know what my defense against that is? Assuming they try and strike with their right hand then what I do is I raise my right arm, block it with my arm and at the same time I punch with my left arm at their left side continue to the face with palm heel strike, and from there I see where I will want to go.

Or even better. Block it like I said above. Round house kick to the groin, which we both know is utterly exposed because of the opponent's attack. Recoil it back so you keep that fighting stance. Grab the opponent right wrist with your right hand, pull it up into motorcycle grip. Switch your grip from the right hand to the left, grab their right shoulder with your right hand. Keep the edge of your right arm against their neck. Yank them down as you knee upwards. Push them back up with the edge of your arm against their neck, then yank back down into your knee. And just keep on doing it until they are so helpless they can't even stand any more. Alternatively, by adjusting your grip while they are bent over you can hammer fist repeatedly to the back of the neck, spine, or kidneys and alternate between that and knees. They'd be down before ten seconds was up.

This isn't speculation, this is fact. A spinning back fist is on the list of the most impractical and foolhardy attacks right next to the sucker punch and the superman punch.

There is a reason why special forces take krav maga. Because it is practical and it can make a person win against multiple opponents.

You said it yourself, your a kick boxing judge. You make sure that the rules are enforced. Do you think that a real fight HAS rules? Do you think real fights are fair?

22. ### billvonValued Senior Member

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There's no difference. There is no "special energy" when something is moving in a curve. The potential energy in a mass is given by 1/2MV^2 no matter how it got there.

Now, you may well be able to accelerate something to a higher speed by moving it in a curve (i.e. swinging a weight at the end of a rope, or a fist at the end of an arm.) But the energy coming from momentum depends only on its speed and mass.

23. ### originHeading towards oblivionValued Senior Member

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11,124
The force of a punch is Mass x Accleteration. It is the accleration of the fist hitting the other guy - the deceleration of the fist into the target. More importantly ideally the fist will not decelerate as much as you will acclerate the target in the opposite direction. It does not matter where the punch is coming from it is all about the velocity, but more importantly the mass or really the effective mass.

If I stand straight up and hit a punching bag with my fist and the rest of my body does not move that will be a very weak punch.

If I move my shoulders with the punch it is more powerful because the velocity will increase and the effective mass will increase.

If I move my hips as the blow is being delivered again punch it is more powerful because the velocity will increase and the effective mass will increase because rotation of my whole body.

If I throw my body forward at the same time this is a complete punch.

The trick is to coordinate all of these movements for maximum velocity and maximum effective mass, while not letting the other guy knock the snot out of you. Boxing truly is the sweet science.

Generally an overhand right (or left) is the most powerful punch, for the above reasons (you can get your whole body into the punch).

A round house puch can be very affective but if you do not have the arm and shoulder strength to follow through then the punch will not be that good because a large amount of the force will be transfered to your hand instead of accelerating the target away from the punch.