Super-Strength Physics Question

[Supreme]

If I had ridiculously high strength and hit someone with enough force to send them flying several meters, wouldn't I also send myself backward a (roughly) equal amount? Equal an opposite reactions being what they are.

[austenandrews]

When you lift a barbell to a certain height, shouldn't you also descend an equal distance?

 

-AA

[Vanguard]

I'm no physics expert . . but I don't think so. You can punch someone in real life and knock them down without you yourself being knocked down. I don't see how increasing the scale of the kockdown/knockback would change anything.

[keithcurtis]

That is what would happen if both of you were in microgravity and unbraced. Falling from an airplane for example.

In RL, the puncher's force is transmitted to the target only because their feet (or whatever) are planted on a mch more massive target (the earth). Yes, you are taking the same force as a reaction; that's why you can break a knuckle. You are using a lifetime of experience to minimize the efects upon yourself, though. Your force comes back along your arm, through your body and all the way down to your firmly planted toes. You also usually put a lot of your personal body momentum into a truly effective punch.

This explains why smacking someone's fist with your face has never evolved into an effective martial art.

 

Keith "Sir Isaac" Curtis

[Kristopher]

Keith pretty much covered it.

[lemming]

Originally posted by Kristopher

Keith pretty much covered it.

That he did. Also explains why a real life delivered from the air is not nearly as forceful as one delivered with you feet on the ground.

[Supreme]

Originally posted by austenandrews

When you lift a barbell to a certain height, shouldn't you also descend an equal distance?

 

-AA

That's why gyms have strong floors.

[Supreme]

Originally posted by Vanguard

I'm no physics expert . . but I don't think so. You can punch someone in real life and knock them down without you yourself being knocked down. I don't see how increasing the scale of the kockdown/knockback would change anything.

Well, Keith's comments aside, most of the time when someone gets knocked down from a punch it's because they get pushed off balance, or lose consciousness. They don't usually get knocked down by the force of the blow, even in heayweight boxing matches.

[Supreme]

Originally posted by keithcurtis

That is what would happen if both of you were in microgravity and unbraced. Falling from an airplane for example.

In RL, the puncher's force is transmitted to the target only because their feet (or whatever) are planted on a mch more massive target (the earth). Yes, you are taking the same force as a reaction; that's why you can break a knuckle. You are using a lifetime of experience to minimize the efects upon yourself, though. Your force comes back along your arm, through your body and all the way down to your firmly planted toes. You also usually put a lot of your personal body momentum into a truly effective punch.

This explains why smacking someone's fist with your face has never evolved into an effective martial art.

 

Keith "Sir Isaac" Curtis

Ah! Now we're getting somewhere. But isn't there a limit on how much planting you can do? Isn't there a point, on the super-human scale, when the ground should give way?

 

I'm only curious about this. I'd never burden my players with nit-picking like this.

[TaxiMan]

The puncher has an advantage over the punchee, in that the puncher can spread the force over time. Think haymaker - the puncher pushes against the ground for a thousand milliseconds, pushing as hard as the ground can take. After the second is up, he dumps all that energy into the punchee "instantaneously".

 

If that "instant" is a millisecond there is 1000x more force present during that time, and the earth fractures under the punchee.

 

The puncher has been accelerating the last 1000 milliseconds and really needs to dump the energy into the punchee, or he'll fly forward and land on his face.

[Jhamin]

Originally posted by Supreme

Ah! Now we're getting somewhere. But isn't there a limit on how much planting you can do? Isn't there a point, on the super-human scale, when the ground should give way?

 

I'm only curious about this. I'd never burden my players with nit-picking like this.

 

Here is where we start having to make assumptions.

 

The ground will eventually give way, but only if the target of the punch fails to absorb the force of the blow. If you hit someone hard enough, their neck snaps back and their legs buckle long before the pavement under their feet cracks. If you could find someone strong enough to keep their body rigid while absorbing that kind of force, then yes. The pavement will crack.

 

This is why car crushers can work. The car's frame will give out long before the re-enforced steel plate is it being pressed against will.

[savagewolf]

The point is a blow of such magnitude, in real life, would not knock back the target, it would instead, literally, open a hole in the body of the victim impaling him on the fist of the puncher, if the victim is not invulnerable . If he is, and the assailant is too, they both would fly in opposite directions destroying everything in their path since the kinetic energy would not have dissipated in any way.

It is the case of the irrestible force that encounters the inamovable object

[Guest Kolava]

I thought the conclusion was reached by physicists that the irresistable force would bounce?

[megaplayboy]

Originally posted by savagewolf

The point is a blow of such magnitude, in real life, would not knock back the target, it would instead, literally, open a hole in the body of the victim impaling him on the fist of the puncher, if the victim is not invulnerable . If he is, and the assailant is too, they both would fly in opposite directions destroying everything in their path since the kinetic energy would not have dissipated in any way.

It is the case of the irrestible force that encounters the inamovable object

 

Well, if they're both invulnerable, the kinetic energy might reverberate off of the two and cause a shockwave around them. Think about a sledgehammer hitting a steel door. The door barely gives, and there's a very loud clang. Sound is basically a pressure wave moving through the air. So a powerful enough clang would generate a very powerful pressure wave moving out from the point of impact.

[Foxiekins]

Okay, hold it...

 

Traction comes into play when you move your body... The damage is NOT inflicted by the force of you pressing against the ground and pushing your fist against someone... The damage is inflicted when your fist, which is moving rapidly, impacts them and undergoes a sudden decelleration... Since impacts generally take an amount of time orders of magnitude smaller than the time to throw the punch in the first place, the forces involved are MUCH larger...

 

There is equal and opposite reaction, true... But the force applying to your fist isn't throwing you backwards, it's SLOWING DOWN YOUR FIST'S ALREADY ESTABLISHED FOREWARD MOTION... Likewise, the force applying to whoever you hit is accelerating them from their previous velocity... Any Kinetic Energy that doesn't stay as energy of motion is absorbed by your fist and their body, due to the inelasticity of the collision, and THAT is the cause of the resulting damage...

 

In short, imagine your fist is a speeding car, and it rams into a mailbox... Does the car bounce off and fly backwards...? Not unless it hits something a lot more massive than itself... And someone punching is effectively doing it with a portion of their mass behind it, their entire mass for things like Haymakers for example...

[Dust Raven]

You make me think of kicking in a door. You don't bounce off and fall backward when the door flies in. Your foot just stops.

[Foxiekins]

Exactly...

 

Originally posted by Dust Raven

You make me think of kicking in a door. You don't bounce off and fall backward when the door flies in. Your foot just stops.

 

The door speeds up, and your foot slows down...

[Kristopher]

And if the door doesn't give in?

 

BTW, people typically don't go flying when you punch them.

[AnotherSkip]

They do when I punch them!!!

[BNakagawa]

Originally posted by Kristopher

And if the door doesn't give in?

 

BTW, people typically don't go flying when you punch them.

 

That's because people don't typically get punched by beings capable of ripping bank vault doors off their hinges.

 

$0.02

[keithcurtis]

Originally posted by Kolava

I thought the conclusion was reached by physicists that the irresistable force would bounce?

 

Then it wasn't an irresistable force.

Seriously, the whole irresistable force, immovable object is an impossible thought construct. You cannot posit a universe with both, since they are mutually exclusive absolutes.

 

Keith "if 42 is the answer, you can't know the question" Curtis

 

PS as for the whole rebounding thing, here's a hopefully useful visual image:

Think of a man swinging a huge sledgehammer sideways at a watermelon. The watermelon will bouce away if it is not braced (albeit after taking some damage). If it is mounted to the table, the hammer will destroy it, going right through it. If the watermelon is made of lead, both it and your hammer will likely bounce (depending on your strength and mass and stance). If the lead watermelon is bolted to the table, which is then bolted to the same ground you are standing on, that hammer will bounce and you'll likely break a bone if you aren't prepared to let the hammer do the bouncing for you.

[Dust Raven]

Now why wasn't all this covered on Bill Nye?

[AnotherSkip]

He doesnt have any lead watermelons?

 

 

Nods to "Keith the science guy Curtis"

[Terry Wilcox]

Originally posted by Supreme

Ah! Now we're getting somewhere. But isn't there a limit on how much planting you can do? Isn't there a point, on the super-human scale, when the ground should give way?

 

There's a simple way to test this. Go stand next to a wall. Lean into the wall and push. Do your feet slide back? Now try it while standing on ice. Then try loose soil. Then try it against the front of a moving car. On ice. With only one leg. With wolves biting your leg.

 

That's why superhero physics is different from real world physics. How can Superman lift a car with one hand without bending the frame? If you put your jack in the wrong place you can bend the frame. Why aren't flying heroes covered with bugs after a flight? My car collects bugs at far lower speeds. Why don't Cyclops' eyes blow out the back of his head? Before she joined the X-Men, how did Kitty Pryde walk through walls but not her clothes?

 

Superhero physics is like time travel. If you think about it too much it gives you a headache.

[Supreme]

Originally posted by Terry Wilcox

There's a simple way to test this. Go stand next to a wall. Lean into the wall and push. Do your feet slide back? Now try it while standing on ice. Then try loose soil. Then try it against the front of a moving car. On ice. With only one leg. With wolves biting your leg.

 

That's why superhero physics is different from real world physics. How can Superman lift a car with one hand without bending the frame? If you put your jack in the wrong place you can bend the frame. Why aren't flying heroes covered with bugs after a flight? My car collects bugs at far lower speeds. Why don't Cyclops' eyes blow out the back of his head? Before she joined the X-Men, how did Kitty Pryde walk through walls but not her clothes?

 

Superhero physics is like time travel. If you think about it too much it gives you a headache.

Well, yes, that's one of the things about super-heroes - like any set of myths or legends or tall-tales - they aren't meant to be realistic or even internally consistent. They are impossible on virtually every level. I was just trying to focus on one of the impossibilities.

 

And you raise an interesting point about ice. Are there any rules about knockback while on ice, or in microgravity?