Combining Allomantic Iron/Steel with the Surge of Gravitation

[Xanpheon]

We know that the effects of Feruchemical Iron allows for the enhancing of the relative strength that Allomantic Iron/Steel can produce (see what Wax manages to do... basically any time he decides to stop holding back). But here's the question this raises, at least to me:

Given that the Surge of Gravitation can clearly add to speed someone is accelerated with multiple lashings:
RoW:

Spoiler

Kaladin using the Surge of Gravitation to rip the head of the Pursuer off when he was getting close to losing himself.

Could we achieve similar results to increasing the mass of the Allomancer with F-Iron by using the Surge of Gravitation? And further to this, how would being able to adjust the way that force acts on the body with the Surge of Gravitation interact with the fact that you need to use the body as a counterweight to the actions you attempt to take with the Pushes/Pulls?

Would a half-lashing upwards render you completely incapable of exerting force to do anything that didn't push you away?

Could you use a lashing running perpendicular to a metal post and a carefully modulated Pull to orbit said metal post? Or taken in the opposite direction, could you use a carefully modulated pull and changing the direction of your lashings to slingshot an object you were pulling on around you like a massive hammer throw?

[StanLemon]

This is a good question. While wob imply that Steel and Iron are based on mass rather than weight and if that is indeed true then the Surge of gravitation theoretically wouldn't have any effect on pushes and pulls. A thing so counterintuitive that I doubt we'll see it in the books unless Brandon explicitly wants to play with it.

My guess is that it will be actually treated as the weight determining it. And if that is the case I'm sure there are plenty of fun interactions that can happen.

[Trusk'our he/him]

8 hours ago, Xanpheon said:

And further to this, how would being able to adjust the way that force acts on the body with the Surge of Gravitation interact with the fact that you need to use the body as a counterweight to the actions you attempt to take with the Pushes/Pulls?

Would a half-lashing upwards render you completely incapable of exerting force to do anything that didn't push you away?

I don't believe that Gravitating yourself would impede your ability to Push or Pull on things, since the Allomancy is based on mass while Gravitation changes the direction of gravity.

Spoiler

https://wob.coppermind.net/events/69-shadows-of-self-release-party/#e5907

clyguy

If Wax were to go to Roshar, and--he's a Skimmer, right? So he can change his weight--if he got Lashed in a different direction if he Stored his weight would that nullify some of the Lashing?

Brandon Sanderson

Okay, you're going to make me think through this. *laughter* So Wax actually changes mass. And the Lashing only affects gravitational pull. So the answer is no because different things with different masses fall at the same speed.

 

8 hours ago, Xanpheon said:

Given that the Surge of Gravitation can clearly add to speed someone is accelerated with multiple lashings:
RoW:

  Hide contents

Kaladin using the Surge of Gravitation to rip the head of the Pursuer off when he was getting close to losing himself.

Could we achieve similar results to increasing the mass of the Allomancer with F-Iron by using the Surge of Gravitation? 

Did this count as speed, or just raw force? Because things can only fall at a certain speed, regardless of their mass, but more pulling force can certainly be achieved. Skimming would interact weirdly with this, but it wouldn't speed you up past removing air resistance because that's not how gravity works.

Spoiler

https://wob.coppermind.net/events/98-worldbuilders-ama/#e867

Bat_Mannington

If a Windrunner lashed Wax upwards, could he dump all of his weight into his metalminds and be unaffected or would the lashing affect his clothes and whatever else he had on him too?

Brandon Sanderson

Wax could mitigate the effect (unless he was in a vacuum) but not eliminate it completely.

faragorn

Vacuum or freefall?

It can be easy to confuse them in the context of surface to orbit.

Brandon Sanderson

I was talking about a Vacuum, but it's good to clarify. What I'm saying is that without wind resistance, his mass doesn't matter--and the books have established that what Wax does is a freakish transformation of his mass, not just his weight.

Kaladin changes how much gravity pulls on someone, and in what direction. Wax (basically, it's more complex than this) changes how much mass he has. The two, then, have some very distinctive effects.

 

Edited November 10, 2025 by Trusk'our

[Xanpheon]

13 hours ago, Trusk'our said:

I don't believe that Gravitating yourself would impede your ability to Push or Pull on things, since the Allomancy is based on mass while Gravitation changes the direction of gravity.

  Hide contents

 

 

Did this count as speed, or just raw force? Because things can only fall at a certain speed, regardless of their mass, but more pulling force can certainly be achieved. Skimming would interact weirdly with this, but it wouldn't speed you up past removing air resistance because that's not how gravity works.

That's a fair point RWT to the Gravitation, I wasn't aware of the WoB regarding that - I couldn't find it anywhere on Arcanum, but I was likely just searching wrong. It does open up some weird conservation-of-momentum tricks if you're "gravity-less" by removing the friction against a surface you can normally rely on, but that's a fair point.

 

As for the "speed" comment, I meant speed (or more accurately put, rate) of acceleration. I know that there's a limit to the speed someone can fall, but my question is more relating to...

Ok, the specific example I want to give here is something like this:
 

In this hypothetical situation, the Radiant/Allomancer is wanting to deliver one massive impact push. The force, and thus rate of acceleration they can apply to themselves, is proportionate to the number of lashings they have applied to themselves.

In principle, could the radiant:

1. Apply multiple lashings to themselves, horizontally, in the direction of their target - accelerating them very strongly in that direction, increasing their momentum significantly.
2. While accelerating, launch a powerful push on a coin in front of them.

This should, going by the equivalent/opposite effect, act almost like a Newton's Cradle - combining the acceleratory force of the multiple times gravity with the sudden massive force of the push.

Because of the way the conservation of momentum works here (as opposed to pushing harder against a much larger mass allowing for a relative greater force to be applied via skimming, you're combining the directional force of the multiple times gravity and the push), it should apply more force and thus accelerate the coin much faster than otherwise, right?

[Trusk'our he/him]

6 hours ago, Xanpheon said:

As for the "speed" comment, I meant speed (or more accurately put, rate) of acceleration. I know that there's a limit to the speed someone can fall, but my question is more relating to...

Ok, the specific example I want to give here is something like this:
 

In this hypothetical situation, the Radiant/Allomancer is wanting to deliver one massive impact push. The force, and thus rate of acceleration they can apply to themselves, is proportionate to the number of lashings they have applied to themselves.

In principle, could the radiant:

1. Apply multiple lashings to themselves, horizontally, in the direction of their target - accelerating them very strongly in that direction, increasing their momentum significantly.
2. While accelerating, launch a powerful push on a coin in front of them.

This should, going by the equivalent/opposite effect, act almost like a Newton's Cradle - combining the acceleratory force of the multiple times gravity with the sudden massive force of the push.

Because of the way the conservation of momentum works here (as opposed to pushing harder against a much larger mass allowing for a relative greater force to be applied via skimming, you're combining the directional force of the multiple times gravity and the push), it should apply more force and thus accelerate the coin much faster than otherwise, right?

I think that would work, but let me ping someone who actually understands physics and isn't just quoting a WoB.

@DrPhysics?

Edited November 11, 2025 by Trusk'our

[DrPhysics he/him]

On 11/11/2025 at 2:36 AM, Xanpheon said:

1. Apply multiple lashings to themselves, horizontally, in the direction of their target - accelerating them very strongly in that direction, increasing their momentum significantly.
2. While accelerating, launch a powerful push on a coin in front of them.

This should, going by the equivalent/opposite effect, act almost like a Newton's Cradle - combining the acceleratory force of the multiple times gravity with the sudden massive force of the push.

Yes, this should work.  The downward lashings would be comparable to having a strong anchor, but the forward motion would keep you closer to the coin allowing you to push harder, longer. 

However, there are two big caveats to this. One, you would up the coin's knock back, but you wouldn't speed it up very much (see this discussion: 

 

The coin is already moving so fast they there just isn't much time to push on it. However, once it slams into a target, it will still have all that force left behind it.

 

The other consideration: you don't want to miss. Hitting a solid object with a coin would hurt. (Remember Vin getting knocked back by the door?) This suggests that allomancers push with a constant power, rather than a constant force, and having all that extra power in the coin would slam into you, and it would not be fun.

 

If it helps, here's a thread I wrote a while ago that summarizes everything we know about pushing physics, and it might help with some of your theorizing:

 

 

 

Edited November 13, 2025 by DrPhysics
Fixing hyperlink