Steelrunning, Kinetic Energy, and Physics

[Trusk'our]

Steelrunners are a bit wonky in how they deal with physics (like F-iron); they are able to resist the force of the Gs put on their body from moving quickly, but aren't able to endure the extra heat caused by friction or air compression.

The thing that I'm confused on right now is that F-steel is somewhat temporal in nature (i.e., they can even Allomantically burn their metals faster), which probably means their interaction with physical objects is similar to that of A-Bendalloy. Does this mean that if a Steelrunner punched an enemy while tapping 3x their normal speed that it still wouldn't hit with any more force than if they hadn't tapped speed, similar to how A-Bendalloy siphons off the extra energy of things that enter and exit it?

What if they instead picked up a club and swung it at an enemy at 3x speed? It's not technically effected by their Feruchemy (F-steel being completely internal as opposed to A-Bendalloy), so the extra speed shouldn't be siphoned off no matter how Feruchemical speed works. But if this is the case, would the Steelrunner have to put 3x the strength into swinging it, making it much, much harder to actually use their speed? 

And if part of a Steelrunner's adaptation of their Spritweb to the use of steel Feruchemy is to enhance their strength to deal with this difficulty with interacting with objects at high speed, would this contribute to a Steelrunner's Feruchemical attribute being overall less efficient than other Feruchemical powers, as more Investiture must be siphoned off to deal with the consequences of using that power?

[Treamayne]

1 hour ago, Trusk'our said:

Steelrunners are a bit wonky in how they deal with physics (like F-iron); they are able to resist the force of the Gs put on their body from moving quickly, but aren't able to endure the extra heat caused by friction or air compression.

The thing that I'm confused on right now is that F-steel is somewhat temporal in nature (i.e., they can even Allomantically burn their metals faster), which probably means their interaction with physical objects is similar to that of A-Bendalloy. Does this mean that if a Steelrunner punched an enemy while tapping 3x their normal speed that it still wouldn't hit with any more force than if they hadn't tapped speed, similar to how A-Bendalloy siphons off the extra energy of things that enter and exit it?

I think that if a ferring sped up and hit something at 3x (or more) speed, the steelrunner would crush their hand, break their arm and/or dislocate joints. I think there is a reason we haven't seen a steelrunner use their feruchemy this way, and that's because they already know this. For example (WoA Ch 58):

Spoiler

Marsh would be able to use it as a weapon against him. So Sazed tapped steel. Allomancy and Feruchemy had one fundamental difference: Allomancy drew its powers from the metals themselves, and so the amount of power was limited; in Feruchemy, one could compound an attribute many times, drawing out months’ worth of power in a few minutes.

Steel stored physical speed. Sazed zipped across the room, air rushing in his ears as he shot past the open doorway. He snatched the lamp out of the air, then tapped iron hard—increasing his weight manyfold—and tapped pewter to give himself massive strength.

Marsh didn’t have time to react. He was now Pulling on a lamp held in Sazed’s inhumanly strong, inhumanly heavy, hand. Again, Marsh was yanked by his own Allomancy. The Pull threw him across the room, directly toward Sazed.

Sazed turned, slamming the lamp into Marsh’s face. The metal bent in his hand, and the force threw Marsh backward. The Inquisitor hit the marble wall, a spray of blood misting in the air. As Marsh slumped to the ground, Sazed could see that he’d driven one of the eye-spikes back into the front of the skull, crushing the bone around the socket.

If just striking with increased speed wouldn't hurt the feruchemist as well, why didn't Sazed just strike Marsh quickly (he could have followed with the Pull, and used both sources of increased momentum), instead he balanced the Speed with Iron and Pewter to make sure he wasn't hurt by striking with his own increased speed. Even in HoA when we see Sazed strike with F-Steel (but no pewter) he still uses F-Iron to baalnce it out (Ch 78)

Spoiler

Sazed released the metalmind, then began to fill it instead, making his body incredibly light. He touched his foot to the steel lock, and tapped speed. Suddenly, he was faster than any man had a right to be. He stood up even as the other four guards turned toward him in surprise.

He stopped filling his ironmind, regaining normal weight, then reached with a blurring speed to pick up the hammer of the fallen soldier. He didn’t have enhanced strength, but he had speed. He slammed the hammer down on a kandra shoulder, growing heavier to add to the momentum of his blow.

The kandra’s bones shattered. 

And in SoS, Bleeder only uses speed with knife-based slashing attacks or when shooting.

1 hour ago, Trusk'our said:

And if part of a Steelrunner's adaptation of their Spritweb to the use of steel Feruchemy is to enhance their strength to deal with this difficulty with interacting with objects at high speed

I don't think it does increase strength, or at least not appreciably - the WoB says there is a slight mental component (similar to Zinc) because at-speed you have to sense and react to the environment quickly (which he compares to the strength component of F-Iron). Increased metal burn is simply a by-product of speed increasing everything about your body - metabolism included (which may imply a similar F-Bendalloy reduced food need when storing speed because of the decreased metabolism and decreased calorie usage).

Spoiler

Brandon Sanderson

I see what you're asking. The mind-altering effects of [Feruchemical steel] are similar to the slight strength you gain from [Feruchemical iron]--it is your Spiritual nature adapting to the new influx of an attribute that it's not really expecting, and siphoning some of that investiture to make you capable of actually using it. So there is a slight temporal effect here, but nothing as big as I think you're looking for.

 

[alder24]

10 hours ago, Trusk'our said:

The thing that I'm confused on right now is that F-steel is somewhat temporal in nature (i.e., they can even Allomantically burn their metals faster)

F-steel stores physical speed of your body, and the speed of your metabolism is also a part of it, thus the speed at which you burn metals can be changed by F-steel. Additionally F-steel does change your mental speed to some small degree.

Spoiler

Alteroden

With [Feruchemical] zinc, you get mental speed. How is that any different from [Feruchemical] steel, except without [physical] speed?

Brandon Sanderson

I think of the mental speed actually turning you into... Let's say you sped up your body, and you wanted to figure out some really complex equations.

Alteroden

So it lets you have intuitive leaps.

Brandon Sanderson

Right. It basically turns you into Ken Jennings. That's how I imagine it.

Kurkistan

So it's not like bullet time?

Brandon Sanderson

No... It'll bullet time a little bit, it certainly will, because you're thinking faster than everyone else, but it has applications beyond bullet timing. Bullet time is really--

Kurkistan

That’s steel’s thing?

Brandon Sanderson

That’s kind of steel's thing. They kind of overlap on that one, because the steel thing... But yeah. It's more like "I think fast, but my reaction speed is not sped up".

Shadows of Self Chicago signing (Oct. 12, 2015)

 

Spoiler

Nadine

You have created some fantastic, original and well thought out magical systems. Where did you get the inspiration for the metal-based system of the Mistborn series and the breath-based system of Warbreaker?

Brandon Sanderson

Thank you! During the early days of my career—before I got published—I found myself naturally creating a new magic system for each book I wrote. I'm not sure why I did this. I just found the process too involving, too interesting, to stop.

For Mistborn, I came to the book wanting several things. I wanted a great magic system that would enhance the graceful, martial-arts style fights. This was going to be a series of sneaking thieves, assassins, and night-time exploration. And so I developed the powers with a focus on that idea. What would make the thieving crew better at what they did? I based each power around an archetype of a thieving crew. The Thug, the Sneak, the Fast-talker, etc.

At the same time, I wanted to enhance the 'industrial revolution' feel of the novels through the magic system. I wanted something that felt like an industrial-age science, something that was a good hybrid of science and magic. I found myself drawn to Alchemy and its use of metals, then extrapolated from that to a way to release power locked inside of metal. Metabolism grew out of that. It felt natural. We metabolize food for energy; letting Allomancers metabolize metal had just the right blend of science and magic.

[...]

Barnes and Noble Book Club Q&A (July 8, 2009)

 

10 hours ago, Trusk'our said:

which probably means their interaction with physical objects is similar to that of A-Bendalloy. Does this mean that if a Steelrunner punched an enemy while tapping 3x their normal speed that it still wouldn't hit with any more force than if they hadn't tapped speed, similar to how A-Bendalloy siphons off the extra energy of things that enter and exit it?

No. They are physically faster, their body is faster, and the equation for kinetic energy is E=mv^2/2 - a punch like that would hurt a lot more. In HoA we see Sazed tapping speed to add energy to his hammer strikes during his confrontation with Kandra, HoA ch 78:

Quote

He stopped filling his ironmind, regaining normal weight, then reached with a blurring speed to pick up the hammer of the fallen soldier. He didn't have enhanced strength, but he had speed. He slammed the hammer down on a kandra shoulder, growing heavier to add to the momentum of his blow.
The kandra's bones shattered. Sazed snapped his foot on the lock and tapped all of the remaining speed. He crouched, pivoting, and slammed his hammer into the knees of two kandra who were trying to attack him with their own hammers.
They cried out, falling, as Sazed's speed ran out

 

10 hours ago, Trusk'our said:

What if they instead picked up a club and swung it at an enemy at 3x speed? It's not technically effected by their Feruchemy

It is, the energy, the speed of your body is transferred into the club, that's what your muscles are doing. If that wasn't the case the club would snap in your hands as the tip of it would want to go at the "normal" speed while your hand would go at 3x speed. Tbf, this doesn't make any sense. You are physically faster, and thus you can throw or move objects with your hands faster.  A club would receive energy from your movement.

Steelrunners can't endure the heat of the atmosphere because that's friction, that's the force of the air acting on their body, heating it up and damaging it. Acceleration is a part of your physical speed, thus you can make an argument that G-forces are tangentially related and thus Feruchemy adapts your body so you can withstand it. Friction of the atmosphere is an external factor. 

 

8 hours ago, Treamayne said:

I think that if a ferring sped up and hit something at 3x (or more) speed, the steelrunner would crush their hand, break their arm and/or dislocate joints. I think there is a reason we haven't seen a steelrunner use their feruchemy this way, and that's because they already know this. For example (WoA Ch 58):

I agree. However Sazed was slamming his hammer with increased speed (or Bleeder with a knife), his wrist would snap, or at least hurt if that was the case. I’m conflicted, but there are limits to this as well. Newton's 3rd Law is applied here, and your body isn't stronger, thus it should get damaged by fast impacts, even those made with hammers or knives if they are too fast. 

[Treamayne]

26 minutes ago, alder24 said:

I agree. However Sazed was slamming his hammer with increased speed (or Bleeder with a knife), his wrist would snap, or at least hurt if that was the case. I’m conflicted, but there are limits to this as well. Newton's 3rd Law is applied here, and your body isn't stronger, thus it should get damaged by fast impacts, even those made with hammers or knives if they are too fast. 

Exactly. My personal headcanon, since there is a derth of detail in those scenes, is this:

• When Sazed struck Marsh with the candelabra, he was specifically using F-Iron and F-Pewter to strengthen himself for a blow with increased speed
• When Sazed used the Kandra hammer, he was only using F-Iron, but he also does not say how much he sped up - a basic 50% increase would still be a huge boost to a weapon as heavy as a sledgehammer without adding enough impac damage to hurt his wrist (since the lever simple-machine concept placing his hand at the fulcrum means the amout of force felt at the fulcrum is a fraction of what would be imparted at the hammer's head) - and he was using F-Iron so there is some resilience
• When Bleeder slit throats with the knife, I imagine she was using the "standard" motion that would derive all the benfitis of speed but without the problem of velocity based damage to herself - from behind and drawing the knife in a "cease" motion (if right handed, then from behind - left to right - across the front of the throat)
  • This would place the friction at the cutting edge but without pushing force into the hand weilding the knife

Another book series (Seven Kennings) highlights this problem well and shows it on-screen repeatedly.

Blight of Blackwings, Seven Kennings Book 2, by Kevin Hearne - Spoiler(ish):

Spoiler

Context: A Courier is blessed by the Kenning of Earth to move extremely quickly - and all people blessed with any Kenning are immune to damage from that source, so they can never be harmed by Earth or Stone - but it does not prevent harm from external forces:

Quote

I was on the road at dawn, with the wind in my hair and bugs splattering my goggles as I traveled south at top speed.

Quote

Moving at full speed and screaming incoherently, I kneecapped all the giants near him with my cudgel so that they would fall to the point where I could slash their throats, dashing in and out of their guard before they could react and getting splashed by their arterial spray. I didn’t stop until I’d dislocated both my shoulders from the speed of the impacts. My wrists were also sprained, in spite of my bracers

So, they have to wear armor and goggles whenever they run with-speed or the damage from just insects can be enormous, and they wear breacers and grieves to reinforce wrist and ankle joints from damage - but weilding a weapon at-speed can still sprain or dislocate joints - or even break their own bones.

 

[therunner]

I would point out that one thing seems to point against the 'destructiveness' of F-steel, and that is that both Bleeder and Marasi interact with everyday objects without damaging them in any way.

For example, Bleeder is easily opening doors at ~15x fold acceleration easily without doing any damage to them.
Marasi on the other hand, grabs multiple glass vials while accelerated at least ~150x, and she does not simply shatter them by grabbing and moving them at such speed.

So something wonky is happening when Steelrunner interacts with other objects, and I don't think it will be as simple as 'Steelrunner swings 3x as fast and so hits 3x as hard'.