Questions about kenetic impacts

[JoeRoccoCassara]

If you had Super strength, and you punched some one in the head or stomach would they really go flying 30 to 40 feet like in comics, or would your fist drill a hole through their head or stomach?

[GAHD]

depends, but likely they'd just go flying(or tumbling with nasty whip-lash on a head-hit). For it to smash through it would have to be moving faster than the speed of sound in the medium it's hitting or the medium would have to be mechanically restricted from bouncing away; thus someone with super-speed would be more likely to go through, while super strength would just not be stopped by the squishy in front of it.

[CraigD]

If you had Super strength, and you punched some one in the head or stomach would they really go flying 30 to 40 feet like in comics, or would your fist drill a hole through their head or stomach?

Punching or pushing (there’s no clear dividing point between these, an effective punch involving a lot of post-impact pushing), with more or less than superhuman force and speed, is governed by the usual three laws of motion. An important thing this tells us is that, unless a superhero is careful to anchor themselves before applying superhuman force to their fists or foes, whatever “knockback” their target experiences, so will they: a horizontal push, however it’s done, that sends a foe sliding horizontally for 30 to 40 feet will also send the superhero about the same distance in the opposite direction.

 

Assuming that the superhero can brace himself properly (eg: against a heavy vertical wall of some height, or by digging a pit in the ground), there’s nothing physically unreasonable about them throwing a foe a long distance in a parabolic trajectory. Alternately, if the superhero is very massive – say 100 times as massive as their foe - they could knock and throw him around the same way you or I can with an object we outmass by a factor of 100, such as a softball.

 

The idea of a superhero of ordinary human shape, height, and mass sending foes flying tens of feet by performing maneuvers that look like ordinary boxing or other martial art, on an ordinary surface such as a city street, is physically unrealistic. The superhero’s need to anchor himself to something massive to avoid slipping about as dramatically as his foe would require strange looking maneuvers. I imagine it would look something like the maneuvers you use when moving an massive, awkward piece of equipment, such as a safe or piano, but much faster, with the “piano” moving swiftly tens of feet rather than slowly inches. In short, it would look weird, very little like a normal melee.

 

In addition to the bracing problem, a super-strong, super-fast person would have significant problems actually moving around quickly in order to set up for their strange combat maneuvers. As their quickness and maximum speed of movement increases, they experience the ordinary world the way an ordinary person would experience a world made of ice-slick surfaces in reduced gravity. Thus, they’d likely try to push off fixed objects, grab railings, etc. I imagine it would look somewhat like a combination of a person negotiating an icy walkway, and an astronaut moving around a space station, but, again, much faster.

 

A punch “drilling” through any part of a foe’s human body is implausible. Drill, spikes, bullets, etc. put holes in people because they’re sharp – that is, they contact the body over a very small area. Increasing this area significantly causes impacts not to penetrate the skin - consider, for example a ”bean bag” shotgun shell.

 

An ordinary human head and its attachments to the spine are remarkably fragile. Hitting a person in the head with much greater than normal human strength and speed is very dangerous. Without doing any detailed calculations, I’m pretty confident we can assume that causing a person to fly tens of feet by a blow or push to their head would be lethal. A drop of between 1.2 and 1.8 m is used to execute people by hanging, fracturing the cervical spine. From which we can reason that an uppercut to the jaw that can lift a person to a similar height would have the same effect, instantly killing them.

[JoeRoccoCassara]

A punch “drilling” through any part of a foe’s human body is implausible. Drill, spikes, bullets, etc. put holes in people because they’re sharp – that is, they contact the body over a very small area. Increasing this area significantly causes impacts not to penetrate the skin - consider, for example a ”bean bag” shotgun shell.

 

So if Superman lifted a massive object, he would go right through it instead of moving it?

[GAHD]

If he lifted a "large' massive object, yes. And if you're talking the golden age superman who couldn't fly, it would probably drive him into the ground like a tentpeg.

 

I gotta kinda disagree with the going through thing, Craig. As an example;

I swing a sledgehammer at a wall. the sledgehammer is blunt, but upon striking said wall with enough speed a hole will be punched through it. The size of the hole is inversely proportional to the speed at which the head hit and still broke the object(just enough speed makes a bigger hole than too much). Same thing with hitting any material free-standing: it is the speed of the hit that determines break vs. bounce. If you don't believe me, try it. I recommend a 22oz framing hammer and a piece of standing plywood, gypsum board, concrete board, cinder block, latex modified water barrier, or whatever you have available. to get that extra speed, you just give it a flick of the wrist :applause:

 

The bean bags don't go through because they have a much lower velocity: ~70-90m/s@muzzle according to wiki, Vs...~500m/s+ at muzzle for a regular shotgun round.

[JoeRoccoCassara]

If he lifted a "large' massive object, yes. And if you're talking the golden age superman who couldn't fly, it would probably drive him into the ground like a tentpeg.

 

I gotta kinda disagree with the going through thing, Craig. As an example;

I swing a sledgehammer at a wall. the sledgehammer is blunt, but upon striking said wall with enough speed a hole will be punched through it. The size of the hole is inversely proportional to the speed at which the head hit and still broke the object(just enough speed makes a bigger hole than too much). Same thing with hitting any material free-standing: it is the speed of the hit that determines break vs. bounce. If you don't believe me, try it. I recommend a 22oz framing hammer and a piece of standing plywood, gypsum board, concrete board, cinder block, latex modified water barrier, or whatever you have available. to get that extra speed, you just give it a flick of the wrist :applause:

 

The bean bags don't go through because they have a much lower velocity: ~70-90m/s@muzzle according to wiki, Vs...~500m/s+ at muzzle for a regular shotgun round.

 

 

I'm actually not talking about the Superman from DC comics, rather the Superman from the 1978 film, and from Superman Returns. Both of which can fly.

[CraigD]

I gotta kinda disagree with the going through thing, Craig. As an example;

I swing a sledgehammer at a wall. the sledgehammer is blunt, but upon striking said wall with enough speed a hole will be punched through it. The size of the hole is inversely proportional to the speed at which the head hit and still broke the object(just enough speed makes a bigger hole than too much). Same thing with hitting any material free-standing: it is the speed of the hit that determines break vs. bounce. If you don't believe me, try it. I recommend a 22oz framing hammer and a piece of standing plywood, gypsum board, concrete board, cinder block, latex modified water barrier, or whatever you have available. to get that extra speed, you just give it a flick of the wrist :hihi:

How about hammer vs. a decent human analog, like a large piece of steak, that Mythbusters favorite, a pig carcass, or the poor man’s alternative, an uncooked chicken?

 

My “must be sharp to penetrate” claim assumed that what’s being penetrated is roughly as strong and elastic as a human being. Being made in large part of long interlocking “fabrics” of protein selected by epochs of evolution to resists penetration, we, like nearly all large animals, are very strong and elastic.

 

Concrete block, sheetrock, etc, on the other hand, is fairly strong, but not very elastic. I can fairly easily punch a neat hole through .5” sheetrock with my bare fist (though, as a general rule, I try not to very often, especially when I’ve been drinking ), and know people who can knock a hole in an 8” block wall with their fists (Unless you’re trained, don’t try this at home! Part of training for “breaking” in martial arts actually increases the density of your hand bones, without which it can be them that do the breaking, not the block!).

 

I personally have never cleanly punched a hole in a standing piece of 3/4" plywood with a single strike with the blunt face of a carpenter’s hammer (I’ve never owned, and only a few times used a heavier, longer-hafted framing hammer), but don’t doubt it if GAHD says he has. In good condition (ie: not rotten) plywood’s falls somewhere between block and animal tissue in terms of elasticity.

 

A quick, rough human analog can be made by covering the target building material with a bit of carpeting. A hammer blow won’t penetrate the carpeting, but will crush the material – pretty similar to what happens when a human is hit somewhere with flat bones and little soft tissue “padding”, such as the face.

 

Take a careful actual look (via slow-motion video, or imaginatively) at a hammer vs. block impact, and you’ll see that what happens is that the fairly strong but brittle block breaks along some well-defined crack line. More flexible stuff, like carpet or meat, deforms, stopping the hammer without being penetrated.

 

Taking a look at hammer vs. thicker concrete, such as a poured foundation or sidewalk, you’ll see that a fairly thin layer of material is broken under the hammer into debris from dust to pebble size.

 

Now, consider arrows, bullets, and other sharp penetrators vs. animal tissue. They work by forcing the tissue apart at right angles to their direction of travel, and require much less force.

The bean bags don't go through because they have a much lower velocity: ~70-90m/s@muzzle according to wiki, Vs...~500m/s+ at muzzle for a regular shotgun round.

Neither speed nor area are dominant factors in determining whether a projectile penetrates a particular target. For example, an arrow typically strikes its target at well under 50 m/s, but due to the very small area and sharpness of its point, penetrates a human-equivalent material deeply. A world-class javelin throw tops out at around 20 m/s, but, in the rare/accidental modern use as weapons, can put deadly holes in a variety of animals.

 

Whether a projectile penetrates a target is, AFAIK, determined by several major factors, including: the projectile’s speed; area impacted; shape; and mass; and the target’s strength, elasticity, and complicated factors such as it’s surface “looseness”. An example of “looseness” can be seen in the backstop netting found behind the targets at some archery ranges. The light, tarp-like sheeting (in a couple of ranges I used to frequent, it actually was ordinary nylon/polypropylene tarps, not the expensive stuff linked to) can easily stop an arrow without being penetrated when allowed to hang freely, but if draped over a target, will be penetrated.

 

For a normally clothed human, somewhere between a 70 m/s, 6 cm^2 beanbag round (wikipedia gives the 6 cm^2 figure, while other references give something more like 25 cm^2, which seems to me a more accurate), which never penetrates, and 500 m/s, 2.5 cm^2 rifled slug, which, within an effective range of 100 m or so, always do, is some shotgun monition that just barely penetrates. Figuring out just where this is would require either some over-my-head engineering modeling, or some experiments involving shotguns, hand-loaded shotgun shells, and something like a turkey or pig carcass dressed in human clothing - a sort of stuff frowned upon in my neighborhood ;).

 

Figuring out the mass and velocity that a super-strong human fist (mine has an area of about 54 cm) would require either advanced engineering modeling, or experiments like the above requiring some sort of large cannon and a fist-like stabilized projectile.

 

I’ll try to get some “burst strength” measurements for some sort of dead animal with the skin on it, using dowels of several diameters – Anybody with a scale and some poultry handy, do the same and post it. With this data, and some measurements we can take of our own bodies, it should be possible to make some estimates of the forces and velocities required for a body-piercing blunt blow in the weird domain of physically realistic comic book superheros. My guess is that the velocity must be very high – over 500 m/s, some 20 times faster than ordinary humanly possible.

[JoeRoccoCassara]

How about hammer vs. a decent human analog, like a large piece of steak, that Mythbusters favorite, a pig carcass, or the poor man’s alternative, an uncooked chicken?

 

My “must be sharp to penetrate” claim assumed that what’s being penetrated is roughly as strong and elastic as a human being. Being made in large part of long interlocking “fabrics” of protein selected by epochs of evolution to resists penetration, we, like nearly all large animals, are very strong and elastic.

 

Concrete block, sheetrock, etc, on the other hand, is fairly strong, but not very elastic. I can fairly easily punch a neat hole through .5” sheetrock with my bare fist (though, as a general rule, I try not to very often, especially when I’ve been drinking :hihi:), and know people who can knock a hole in an 8” block wall with their fists (Unless you’re trained, don’t try this at home! Part of training for “breaking” in martial arts actually increases the density of your hand bones, without which it can be them that do the breaking, not the block!).

 

I personally have never cleanly punched a hole in a standing piece of 3/4" plywood with a single strike with the blunt face of a carpenter’s hammer (I’ve never owned, and only a few times used a heavier, longer-hafted framing hammer), but don’t doubt it if GAHD says he has. In good condition (ie: not rotten) plywood’s falls somewhere between block and animal tissue in terms of elasticity.

 

A quick, rough human analog can be made by covering the target building material with a bit of carpeting. A hammer blow won’t penetrate the carpeting, but will crush the material – pretty similar to what happens when a human is hit somewhere with flat bones and little soft tissue “padding”, such as the face.

 

Take a careful actual look (via slow-motion video, or imaginatively) at a hammer vs. block impact, and you’ll see that what happens is that the fairly strong but brittle block breaks along some well-defined crack line. More flexible stuff, like carpet or meat, deforms, stopping the hammer without being penetrated.

 

Taking a look at hammer vs. thicker concrete, such as a poured foundation or sidewalk, you’ll see that a fairly thin layer of material is broken under the hammer into debris from dust to pebble size.

 

Now, consider arrows, bullets, and other sharp penetrators vs. animal tissue. They work by forcing the tissue apart at right angles to their direction of travel, and require much less force.Neither speed nor area are dominant factors in determining whether a projectile penetrates a particular target. For example, an arrow typically strikes its target at well under 50 m/s, but due to the very small area and sharpness of its point, penetrates a human-equivalent material deeply. A world-class javelin throw tops out at around 20 m/s, but, in the rare/accidental modern use as weapons, can put deadly holes in a variety of animals.

 

Whether a projectile penetrates a target is, AFAIK, determined by several major factors, including: the projectile’s speed; area impacted; shape; and mass; and the target’s strength, elasticity, and complicated factors such as it’s surface “looseness”. An example of “looseness” can be seen in the backstop netting found behind the targets at some archery ranges. The light, tarp-like sheeting (in a couple of ranges I used to frequent, it actually was ordinary nylon/polypropylene tarps, not the expensive stuff linked to) can easily stop an arrow without being penetrated when allowed to hang freely, but if draped over a target, will be penetrated.

 

For a normally clothed human, somewhere between a 70 m/s, 6 cm^2 beanbag round (wikipedia gives the 6 cm^2 figure, while other references give something more like 25 cm^2, which seems to me a more accurate), which never penetrates, and 500 m/s, 2.5 cm^2 rifled slug, which, within an effective range of 100 m or so, always do, is some shotgun monition that just barely penetrates. Figuring out just where this is would require either some over-my-head engineering modeling, or some experiments involving shotguns, hand-loaded shotgun shells, and something like a turkey or pig carcass dressed in human clothing - a sort of stuff frowned upon in my neighborhood .

 

Figuring out the mass and velocity that a super-strong human fist (mine has an area of about 54 cm) would require either advanced engineering modeling, or experiments like the above requiring some sort of large cannon and a fist-like stabilized projectile.

 

I’ll try to get some “burst strength” measurements for some sort of dead animal with the skin on it, using dowels of several diameters – Anybody with a scale and some poultry handy, do the same and post it. With this data, and some measurements we can take of our own bodies, it should be possible to make some estimates of the forces and velocities required for a body-piercing blunt blow in the weird domain of physically realistic comic book superheros. My guess is that the velocity must be very high – over 500 m/s, some 20 times faster than ordinary humanly possible.

 

Even a mile wide edge (Unimaginably blunt) can penetrate (or annihilate) one inch of free falling super elastic spider silk if it moves fast enough. (Some trillions of times faster than light)

 

But if an object a mile big moved that fast (Even with out touching anything) then it wouldn't just annihilate the elastic silk, but a couple of galaxies and itself.

 

DC Comics super heroes such as Pre-Crisis Silver age adult Superman could punch a clean hole through a man. The speed, durability and strength of his arm would easily make up for the blunt and elastic fist.

 

GAHD and you were both right, you just had a misunderstanding. He thought that you meant that a blunt object could never penetrate a human, when you meant that at super 'human' speeds a blunt object could never penetrate a human.