Physics of lifting versus punching?

[Tornado]

Is the idea of a character who can lift a lot but can't punch super hard sensible?  It seems like to lift something requires you to apply a level of force greater than that of gravity (i.e. 9.8 m/s^2 * its mass in kg), which is a very substantial.  So in order to lift a 2000 kg object, you need to apply at least (preferably substantially more, if you want to do it in any reasonable amount of time) 19,600 newtons of force to it.  The human fist has a surface area of ~110 cm^2, according to some googling.  Even assuming you can only apply half that force per hand, that's about 130 psi or 2,000 lbs of force.  For comparison, the hardest punches the best boxers can manage are around ~1000 lbs of force.  The amount of damage becomes more ridiculous the more you can lift.

 

Am I not understanding something?

I want a character who can lift a tank but not necessarily kill someone in a single punch.  Is this even physically plausible?  Yes, yes, it's an RPG not real life, but I need to know.

[Christopher]

Sees such stuff done, usually it is done via "Inertia/Mass Negation".

The character is not actually strong enough to lift the object. He just makes the item light enough that the can lift it. The same way he can lower inertia temporarily to either give the object a decent amount of momentum or stop something with a lot of.

 

Also "who" should he not be able to kill with a punch? A normal person? A agent level foe? Another Super? A brick level defenses super?

There is a ton of room in the durability are between each of those.

[dmjalund]

IMHO damage done by a punch has a velocity cpmponent, i.e. how fast can you accellerate that arm before it hits the target.

 

however, you could put all your lift strength towards holds and squeezes

[sinanju]

IMHO damage done by a punch has a velocity cpmponent, i.e. how fast can you accellerate that arm before it hits the target.

 

however, you could put all your lift strength towards holds and squeezes

 

I was going to make this exact point. Lifting strength and squeezing, crushing strength are probably going to be the same. But your ability to punch something is based as much on how fast you can accelerate your fist as how strong you are. Force = Mass X Acceleration. A very slow punch isn't going to do as much damage no matter how strong you are. Unless you can crush the target against a solid wall.

 

Think of being in zero-g in orbit. A fully loaded railroad boxcar is moving toward you at a fraction of an inch a second. If you're in open space, it's just going to push you along in front of it. If you're caught between that boxcar and another solid, heavy object, you're going to be slowly crushed by it.

[Tornado]

I was going to make this exact point. Lifting strength and squeezing, crushing strength are probably going to be the same. But your ability to punch something is based as much on how fast you can accelerate your fist as how strong you are. Force = Mass X Acceleration. A very slow punch isn't going to do as much damage no matter how strong you are. Unless you can crush the target against a solid wall.

 

Think of being in zero-g in orbit. A fully loaded railroad boxcar is moving toward you at a fraction of an inch a second. If you're in open space, it's just going to push you along in front of it. If you're caught between that boxcar and another solid, heavy object, you're going to be slowly crushed by it.

Right, but isn't lifting power in gravity also determined by the force you can bring to bear?  I mean, if I lift a car over my head, I have to apply more force to it than gravity is already.  Right?

 

Okay, thinking about it again, the damage is probably related to the force from deceleration, which is not necessarily 1:1 correlated to the force from acceleration.  Is that correct?  If so, what is the maximum reasonable relationship?

[Simon]

There are a large number of factors involved in either...though more in the force of a punch.

 

Easy example:  go find an iron dumbbell with about 100 pounds of weight on it.  Lift it over your head.  It's heavy, but you should be able to manage that....if not, then tone the weight down.  Then suspend it in the air (tie a rope to it and attach it to something sturdy).  Try and punch it as hard as you can and see how far you can get it to go upwards.

 

As you wait in the ER for the doctor to x-ray and set your hand/wrist you can ponder the different factors in play for punching vs. lifting.

 

For a counter example:  setup some force pads on a punching dummy.  Punch the pad as hard as you can.  If you've had some training, you should be able to get into the range of 500 - 1000 pounds of force.  Have someone gently lower the same amount of weight onto you and try to lift it.

[Simon]

Also look to empirical evidence:  look at the typical body types of a power lifter vs. a boxer (or MMA fighter) -- the act of lifting/squeezing is almost completely different from the act of striking.  Different muscle groups, different mechanics, and different considerations.

 

You might as well work out the relationship between someone's top sprinting speed and their max punching strength.

[Simon]

Scientific method:

 

You have a theory -- that the force of a punch is directly tied to the physical strength (lifting strength) of an individual.

 

You expand on that theory - this is still in the beginning stages, though you did some in the thread.

 

You see how well your theory matches observed evidence/empirical data.  This is where you run into problems.  There is a wealth of data available on both the subject of lifting strength (look to olympic power lifters, for example) and punching force.  Studies done on boxers, in particular, present evidence that is in direct conflict with your theory.  Some of the strongest punchers in boxing studies are the lighter weight classes (the guys with less muscle and MUCH less lifting strength than the heavy weights).  Not proportionally stronger, just stronger punchers -- they generated the most force. Your theory that lifting strength is tied to punching strength does not account for this and would appear to be disproven by the data at hand.

 

So you need to come up with a different theory.

 

When you look at punching strength and what constitutes a strong punch, you find some rather interesting things that help to explain why some of the most physically strong individuals don't have correspondingly strong punches.  If you have decent muscle definition in your upper arms, make a tight fist while feeling your bicep.  Notice that it's tensing up?  Now feel your bicep while you throw a punch -- notice still more tensing?  That's a problem.  Your bicep is responsible for bending your arm in -- that's the opposite direction that you want to go when throwing a punch.  So you're actively fighting yourself in throwing your punch.  Learning to throw a good punch is more about learning to relax all but the muscles involved in the act of punching itself (and there are a lot of them).  Easier said than done....particularly in that you need to re-evaluate the motion of a punch in order to accomplish this -- your body has some pretty hard-wired controls in place to keep you from hyper-extending your elbow.

 

Those power lifters you thought should have good punching strength?  They have pretty massive musculature -- it's a lot to get moving quickly (another part of a good punch) and it's a LOT to have fighting their basic punching motion.

 

And none of this even starts to get into transference of force, which is a whole other subject in and of itself...

[L. Marcus]

Re. what the muscles do: the biceps is responsible for the flexing in the elbow joint. The triceps is the one extending. [/anatomygeek]

[Simon]

Re. what the muscles do: the biceps is responsible for the flexing in the elbow joint. The triceps is the one extending. [/anatomygeek]

Yeah...I should have been more clear in that...

 

If you want still more fun, work through the muscles that are tensed when you clench your fist...and how that affects your ability to extend your arm during a punch...

[L. Marcus]

And generally, the flexors are stronger than the extensors ...

[Simon]

Ayup...we (as a species) are very grabby. 

 

...which is why it's so hard to learn how to effectively throw a punch ;-)

[L. Marcus]

I blame it on our tree-climbing ancestors.

[megaplayboy]

Punching power is related to arm strength in one narrow way--it's an example of "explosive" strength.  When you lift a weight using your arm, then bring it down to a resting point, then "explode" back up with it, there's some correlation there to the kind of muscle movement  involved in throwing a "power" punch(e.g., a straight cross). 

Boxers and martial artists throw harder punches because they train to throw 1) with proper form, 2) are able to apply a greater proportion of their strength to the punch and 3) through vigorous exercise of the muscles involved, they gain greater strength for those specific movements(i.e., rapid striking movements). 

One way to justify a super-strong character who punches under their weight(so to speak) is to just say that they are untrained and throw punches with bad form(e.g., the so-called "arm punch", where no muscles outside the arm are used). 

[Old Man]

And generally, the flexors are stronger than the extensors ...

 

I think this is backwards, at least for the larger muscle groups.

 

From a physics standpoint, the simple act of punching someone can get pretty complicated to figure out.  Force is about the best way to measure static strength.  Force (mass times acceleration) also gives how hard you hit the victim, in pounds--but that has multiple components, because not only is your arm of a given mass moving at a given velocity at impact, you're also (presumably) still exerting force with the appropriate muscles, so you need to add that in.  Then on the receiving end, what matters is not only force, but impulse--the force integrated over the time that it is applied to the victim.  In most cases the impulse is likely to be about constant, so to maximize force you want to apply the impulse over a minimum amount of time, which roughly means hit him with your knuckles and not your mooshy palm.

 

Finally, you want the collision to have as low a coefficient of restitution as possible, as that means that the maximum amount of kinetic energy is being absorbed by the masses involved--hopefully, the victim.  Since that works as the square of the velocity, obviously you want the velocity of your fist to be as high as possible without sacrificing mass or power.  And so on.

[Simon]

See...this is where we run into some misconceptions, I think.

 

First off, the arm is not as involved as most like to think in a punch.  If you isolate just the arm movement in a good punch, you're looking at about 2 inches of movement of the hand.  The rest comes from the body, with the core muscles being large contributors.

 

Second, open hand (palm heel) vs. knuckle punching doesn't have the relationship that you might think.  Open hand tends to do internal damage while knuckle punching tends to leave the damage at the surface.  Easiest way to think of it is to imagine striking a fish tank.  If you want to break the glass of the tank, you strike it with your knuckles.  If you want to stay dry and kill the fish inside the tank, you do an open palm strike (and hope that your training was good).

[Cancer]

Is the idea of a character who can lift a lot but can't punch super hard sensible?  It seems like to lift something requires you to apply a level of force greater than that of gravity (i.e. 9.8 m/s^2 * its mass in kg), which is a very substantial.  So in order to lift a 2000 kg object, you need to apply at least (preferably substantially more, if you want to do it in any reasonable amount of time) 19,600 newtons of force to it.  The human fist has a surface area of ~110 cm^2, according to some googling.  Even assuming you can only apply half that force per hand, that's about 130 psi or 2,000 lbs of force.  For comparison, the hardest punches the best boxers can manage are around ~1000 lbs of force.  The amount of damage becomes more ridiculous the more you can lift.

 

Am I not understanding something?

 

I want a character who can lift a tank but not necessarily kill someone in a single punch.  Is this even physically plausible?  Yes, yes, it's an RPG not real life, but I need to know.

Yes, the idea of lift lots but can't punch makes a great deal of sense. A jack can lift great weight but cannot inflict impact damage (unless you are weilding it as a weapon).

 

Damage comes from imposing strong (and generally highly localized) accelerations upon parts of a target. You are trying to cause strong internal stress inside the target, so that in places the stress exceeds the maximum strength of the binding forces of the material of the target, and the target breaks/tears/is crushed at those places of excessive stress. Both energy deposition and momentum transfer are involved, but the latter is more important for induction of damage.

 

Liifting generally involves vrey small accelerations, and upward momentum of the lifted object is usually very small, so momemtum transfer is negligible, and usually you want the energy delivered uniformly through the target, causing minimum internal stress.

[Old Man]

See...this is where we run into some misconceptions, I think.

 

First off, the arm is not as involved as most like to think in a punch.  If you isolate just the arm movement in a good punch, you're looking at about 2 inches of movement of the hand.  The rest comes from the body, with the core muscles being large contributors.

 

Second, open hand (palm heel) vs. knuckle punching doesn't have the relationship that you might think.  Open hand tends to do internal damage while knuckle punching tends to leave the damage at the surface.  Easiest way to think of it is to imagine striking a fish tank.  If you want to break the glass of the tank, you strike it with your knuckles.  If you want to stay dry and kill the fish inside the tank, you do an open palm strike (and hope that your training was good).

 

Exactly.  The mechanics and biomechanics involved in striking an opponent are far more complex than most people realize; that was the point of my post, anyway, which was supposed to just scratch the surface as far as figuring out how to model attacks using physics.  I get a little irritated when I see things on TV that supposedly measure how hard someone kicks or punches, and they just give a number in pounds and expect it to mean something.

 

Open hand/knuckle punching has exactly the relationship that you describe, in that the acceleration and energy transfer from the knuckles is faster, which causes damage to stay near the surface as opposed to being dissipated further inside the victim.  Of course, the body part you're trying to damage really defines the most effective type of strike.  If I wanted to KO someone via concussion or brain stem disruption, then I'd want to impart very high acceleration to the head very quickly--so I'd want to use a relatively hard body part to hit with, and the velocity of that body part would be more important than the mass or muscle force behind it.  Conversely, if I wanted to bruise or disrupt internal organs, then I'm trying to impart force to a more massive target through a softer medium, so either I need to achieve displacement of the target with a more massive "weapon", or else disrupt it with a shockwave imparted at the surface, and abrupt acceleration is less important to either of these damage mechanisms.

 

And then there's breaking bones, which is something else entirely...

[Beast]

I would go with Flight usable as an attack equal to your running

then use the weight multiplier for extra lift

 

Forced anti-gravity:  Flight 7", Reduced Endurance (0 END; +1/2), Usable As Attack (x16 maximum weight per inanimate target; +2) (49 Active Points); OIHID (-1/4)

[Cassandra]

Keep it simple

 

+60 STR, Does No Damage (-1/2)

 

Cost 40 Points

[Tasha]

Keep it simple

 

+60 STR, Does No Damage (-1/2)

 

Cost 40 Points

I was going to say "Don't overthink it, it's just a game."

 

A Game that is designed to model Comic/Cinematic Reality. If you bring to much reality into the system it starts to break. Also as you have seen above things are always more complicated than people believe. If you don't believe me see if you can dig up some of the Epic discussions of Guns and how they "should" be "properly" modeled in the system.