Space jump (not FTL, just cool)

[Djarskublar]

@Peng the Just and I were hanging out today, and we decided to do some math and see if a full Feruchemist could do some freaky things. And they totally can. By far the most important metal for this is iron. The conservation of momentum that we see with Wax is very important. I told him about people's idea of using Feruchemical steel and the frictionlessness surge that Lift uses (whatever it is named...). We then were joking around about that, and we came to a question: could a feruchemist jump out of orbit? The short answer is yes, but it would likely kill them and require a solid store to tap out.

Here is the setup: you fill a bunch of power of a few metals into your relevant minds. If you want to survive it, you will need gold, cadmium, and maybe pewter. If you don't mind dying in the process, you only need a bunch of iron and steel. Some pewter doesn't hurt either. The mechanic for how you do this is to tap some speed and a lot of weight. You need to maintain the speed tap for a long time until you leave atmo, so you can't do a very powerful tap unless you are willing to use a spike and become a compounder (totally worth it). Tap some strength too and set it up so you run out in around a quarter second. The instant your feet leave the ground, stop tapping iron and start filling it instead. You still need to tap steel for speed, but that remains constant. If you tap strength to give yourself a more powerful jump, then great. You don't need to do anything with it now.

This works out so that you can get a jump that from iron alone ends up at a huge factor. Tap out for a quarter second everything you've got, and you could probably hit 20x mass for that time fairly easily. Then you store around 3/4 of your mass, and you have a factor of 80. A normal human can jump around a meter high if they are in excellent condition. Say a solid pewter tap allows a jump three times that. That works out to a velocity of around 7.7 m/s when you leave the ground. Toss in a factor of four on your speed tap for the duration of the ascent, and you get an initial velocity of around 2500 m/s. The friction would clearly burn you up very fast, so have your friendly neighborhood Edgedancer apply some awesomeness if that is a thing they can do, or spike your friend if not. If you don't need to be intact when you are going up, that should be a high enough initial velocity to get you to space on Earth. It's only around 30 km to the edge of space. This only gets you to space, though. Escape velocity is going to be somewhere around 12,000 m/s, so you would need to store for a ridiculously long time or be a compounder via Hemalurgy to pull off escape velocity.

You can use a smaller version of this to jump up buildings easily.

Physics! (it's been a while, so feel free to poke holes)

 

Another interesting thing you can do with Feruchemical iron is jump off buildings without a care. Start storing a lot of mass when you jump, and just before you hit the ground start a solid tap. You can use that to decelerate to a manageable speed, and survive any fall. What are parachutes you ask? Irrelevant, I say!

While I'm at it, I open this up to you! Come up with fantastic uses for Feruchemical iron that involve conservation of momentum.

[Landis963]

First off, Lift's Surgebinding of choice is the surge of Abrasion.  Second off, the not-parachute is predicated on the assumption that any Feruchemist, Full or otherwise, would be able to store speed quick enough to not cause injury.  Considering that a major security features of Feruchemy is a cap on how quickly one can store, this seems unlikely.  

[Djarskublar]

7 minutes ago, Landis963 said:

First off, Lift's Surgebinding of choice is the surge of Abrasion.  Second off, the not-parachute is predicated on the assumption that any Feruchemist, Full or otherwise, would be able to store speed quick enough to not cause injury.  Considering that a major security features of Feruchemy is a cap on how quickly one can store, this seems unlikely.  

Ahh, thanks for the Surge.

The not-parachute is actually a mass tap/store, not a speed store. The way it would work is somewhat shown with Wax. When he makes himself lighter while flying, he starts going faster. If you make yourself really light, then jump out of a plane, you will hit whatever terminal velocity you get on whatever planet you are on, then just before you hit the ground, start a sizeable tap, and you will slow down a lot. Enough that you could very easily survive the fall. Your momentum is conserved, so when you add mass, your velocity acts inversely, and you slow down. The only thing that would matter here is how fast you can switch from a sizeable store to a sizeable tap. Any number of examples in book would suggest it is as fast as you want.

[Landis963]

Wouldn't the increased mass speed up your trip down to earth? And how do you define "survive the fall?"  And my concerns about how quickly a Feruchemist could actually store their weight, especially in circumstances such as freefall, are still valid.  

[Spoolofwhool]

37 minutes ago, Djarskublar said:

Another interesting thing you can do with Feruchemical iron is jump off buildings without a care. Start storing a lot of mass when you jump, and just before you hit the ground start a solid tap. You can use that to decelerate to a manageable speed, and survive any fall. What are parachutes you ask? Irrelevant, I say!

I'm fairly certain that while this would greatly decrease your velocity, the force applied to your body in the process would more than likely kill you. This is because while momentum is conserved so mv(initial) = mv(final), kinetic energy would not be conserved since 0.5mv^2initial =/= 0.5 mv^2 final, and the change in kinetic energy would be the result of a force on the body. 

3 minutes ago, Landis963 said:

Wouldn't the increased mass speed up your trip down to earth? And how do you define "survive the fall?"  And my concerns about how quickly a Feruchemist could actually store their weight, especially in circumstances such as freefall, are still valid.  

Increased mass wouldn't increase how quickly you fall since acceleration due to gravity is always constant, without taking air resistance into account. For theoretical applications, mass is independent. 

[Djarskublar]

11 minutes ago, Spoolofwhool said:

I'm fairly certain that while this would greatly decrease your velocity, the force applied to your body in the process would more than likely kill you. This is because while momentum is conserved so mv(initial) = mv(final), kinetic energy would not be conserved since 0.5mv^2initial =/= 0.5 mv^2 final, and the change in kinetic energy would be the result of a force on the body. 

Increased mass wouldn't increase how quickly you fall since acceleration due to gravity is always constant, without taking air resistance into account. For theoretical applications, mass is independent. 

That is a fair point on the kinetic energy. Where would it go? Heat? Some sort of kinetic force that squishes you? PAFO I guess... @PeterAhlstrom

[Spoolofwhool]

5 minutes ago, Djarskublar said:

That is a fair point on the kinetic energy. Where would it go? Heat? Some sort of kinetic force that squishes you? PAFO I guess...

Another question is where the force that's changing the kinetic energy is originating from. Normally in conservation of momentum questions, you have two bodies hitting each other and sticking, or explosions separating things, so the force is from that, but here mass is just... appearing... so the force would just be appearing as well, from some where. So weird. Probably the magic compensates.

[DeTess]

Just a small correction. The Karman line, after which space is generally considered to begin, is located at 100 km altitude, not 30. Your initial jump still easily gets you high enough though, getting as high as 300km if it is done straight up.

Edited October 12, 2016 by randuir
spelling

[Magestar]

I'm not quite getting what the Steel (speed) is being used for.  Would you mind explaining that to me?  I have an idea that might work the way you are thinking, but I'd like to see where you were going with it.

[Djarskublar]

2 hours ago, Magestar said:

I'm not quite getting what the Steel (speed) is being used for.  Would you mind explaining that to me?  I have an idea that might work the way you are thinking, but I'd like to see where you were going with it.

If you use it through the whole jump, it would act as a straight multiplier. It would be useful to add a small multiplier like, say, four. You couldn't go much higher than that without compounding because the tap would have to be maintained for a long time until you hit the peak of your jump.

4 hours ago, randuir said:

Just a small correction. The Karman line, after which space is generally considered to begin, is located at 100 km altitude, not 30. Your initial jump still easily gets you high enough though, getting as high as 300km if it is done straight up.

Hmmm. I thought it was 20 miles, so I converted. I try to use metric for these things, but I live in the US. I just hope I got all my units right. I think I did. Metric is just better.

I thought of another cool thing you could do. Jump laterally for some sweet long jumps. Use it to jump chasms or use it similarly to a burst of superspeed.

The amount of practice this would take to get accurate with your jumps would be tough. I can see many broken bones occurring before you get it down. Lucky they are a full Feruchemist and can just tap gold!

[Magestar]

35 minutes ago, Djarskublar said:

If you use it through the whole jump, it would act as a straight multiplier. It would be useful to add a small multiplier like, say, four. You couldn't go much higher than that without compounding because the tap would have to be maintained for a long time until you hit the peak of your jump.

Ah.  You are operating under the assumption that speed is a straight multiplier, and that it increases velocity, for lack of a better term.  I wonder about that.  I always assume it increases the time in which you can do things, instead of acting as a velocity multiplier.   I could understand the way you are saying it could work, but I've always been prejudiced towards the other way.

[Djarskublar]

3 minutes ago, Magestar said:

Ah.  You are operating under the assumption that speed is a straight multiplier, and that it increases velocity, for lack of a better term.  I wonder about that.  I always assume it increases the time in which you can do things, instead of acting as a velocity multiplier.   I could understand the way you are saying it could work, but I've always been prejudiced towards the other way.

I agree with the time theory. I just think it would still work as a multiplier through the whole flight.

If it doesn't, you could instead just do a large tap on it and use it while jumping to massively accelerate your jump. Either way is cool. The massive tap would provide a better multiplier, though.

[Magestar]

That's what I was thinking.  If gravity has less time to act on you in comparison to how fast you are moving, that would mean that gravity would have a lesser effect, IMO.  I think it would depend on how you think of gravity.  However, if you were falling, and increased the time you had to fall, I feel like you would not speed up in real time.  That's why I don't think it would work the whole time, only while you were exerting the force against gravity.

[Djarskublar]

Another thing it might do is affect how you tap other metals. It could make It so your taps are effectively longer, allowing for higher taps. The physics of Feruchemical steel are annoyingly poorly explained, even in WoB. In the end, there may not be a way to get Feruchemical steel to help with the jump.

[Peng the Just]

My favorite realization: if you reach escape velocity and have stored your weight to where your mass is, say, 20 kilograms on your way up, you still exert close to a million newtons of force on the ground. As you would accelerate during the quarter second you were touching the ground, your acceleration would be 48,000 m/s^2, times your twenty kilo effective mass= 960,000 newtons, which is just over two hundred thousand pounds of force. You would totally leave a crater.

 

Edited October 12, 2016 by Peng the Just
eye cehnt spel.

[cometaryorbit]

On 10/12/2016 at 0:17 AM, Djarskublar said:

Another interesting thing you can do with Feruchemical iron is jump off buildings without a care. Start storing a lot of mass when you jump, and just before you hit the ground start a solid tap. You can use that to decelerate to a manageable speed, and survive any fall. What are parachutes you ask? Irrelevant, I say!

It's a lot easier just to store down to the point that your weight (plus clothes and metalminds) is low enough that your terminal velocity is harmlessly slow. Sazed does it in Well of Ascension.

[Emerald101]

On 10/11/2016 at 11:59 PM, Spoolofwhool said:

I'm fairly certain that while this would greatly decrease your velocity, the force applied to your body in the process would more than likely kill you. This is because while momentum is conserved so mv(initial) = mv(final), kinetic energy would not be conserved since 0.5mv^2initial =/= 0.5 mv^2 final, and the change in kinetic energy would be the result of a force on the body. 

Increased mass wouldn't increase how quickly you fall since acceleration due to gravity is always constant, without taking air resistance into account. For theoretical applications, mass is independent. 

It's possible that you would actually survive that force, because of how feruchemical iron strengthens the body. It's hard to say without a quantitative measure of how much of an effect that strengthening gives.

edit: Are we sure that it is indeed momentum which is being preserved? I know that we see wax manipulate his velocity via manipulation of mass in the books, but could it be energy that's being preserved? A decrease in mass at constant energy would result in an increase of velocity, just not a proportional increase.

Edited October 19, 2016 by Emerald101
additional comment

[Spoolofwhool]

On 10/14/2016 at 7:10 PM, cometaryorbit said:

It's a lot easier just to store down to the point that your weight (plus clothes and metalminds) is low enough that your terminal velocity is harmlessly slow. Sazed does it in Well of Ascension.

I thought Sazed stored his mass in order to decrease his downward force due to gravity so he would have an easier time climbing down. Storing mass when falling wouldn't change acceleration due to gravity, just that you would have less downward force.

As you suggested, decreasing mass would decrease terminal velocity, at a square root rate, so it would have a difference if you decrease mass significantly. I did some math and found that someone with a mass of 8.07 kg would have a terminal velocity of around 5.7 m/s, meaning their landing would be the same as if a regular person fell around 1.7 m. So, that is, in fact, a doable landing strategy, one which would actually work out to be more effective, assuming my math is correct.

2 hours ago, Emerald101 said:

It's possible that you would actually survive that force, because of how feruchemical iron strengthens the body. It's hard to say without a quantitative measure of how much of an effect that strengthening gives.

edit: Are we sure that it is indeed momentum which is being preserved? I know that we see wax manipulate his velocity via manipulation of mass in the books, but could it be energy that's being preserved? A decrease in mass at constant energy would result in an increase of velocity, just not a proportional increase.

Good point. The extra strength the feruchemy grants to normally support the extra mass wouldn't be necessary in a freefall and could therefore help guard against the force of change. Didn't think of that, though it would be hard to quantify if it would be enough. 

You are could be correct. It's either a conservation of momentum or conservation of energy. However, since feruchemy is removing energy from the system when storing (potential energy decreases), it would make sense for it to be adding energy when you tap, which is what is happening during the conservation of momentum scenario. (potential energy is increasing far more than kinetic energy is decreasing) Either way, there would be some sort of force applied to provoke the change. 

[cometaryorbit]

54 minutes ago, Spoolofwhool said:

As you suggested, decreasing mass would decrease terminal velocity, at a square root rate, so it would have a difference if you decrease mass significantly. I did some math and found that someone with a mass of 8.07 kg would have a terminal velocity of around 5.7 m/s, meaning their landing would be the same as if a regular person fell around 1.7 m. So, that is, in fact, a doable landing strategy, one which would actually work out to be more effective, assuming my math is correct.

Yeah, and Sazed became very light. "The thin metal bracelets on his legs were the heaviest things on his body, and they kept him pointed feet-downward." The metalminds can't weigh that much - they're specifically described as thin. I'd figure he's probably down around 1-2 kg or so; significantly less if the bracelets are actually heavier than his whole body rather than just heavier than any one limb/the head/whatever.

[Djarskublar]

Speaking of, when Wax escapes the explosion in AoL, he was heavier than a building. Apparently my numbers for tapping were extremely conservative.

[Eki]

Momentum being conserved has been confirmed by WoB, but things get really weird when mass changes like that.

[The Ninja Yodeler]

I... Am so lost. 

[Djarskublar]

1 hour ago, The Ninja Yodeler said:

I... Am so lost. 

The basic idea is that your initial velocity times your mass is your momentum, so if you change your mass via iron feruchemy, then your velocity changes a proportional amount. m1v1=m2v2

I imagine this would look a lot like Force leaps in Star Wars. They would be much more powerful, though. 

If Wax can make himself as heavy as a building and Sazed made himself light as a feather, then that is a huuuge multiplier. Call it something like a factor of 50000:1... That is some insane acceleration.

[Jedal]

Just in terms of general Feruchemal power, wouldn't someone with the full powers of a Feruchemist who had access to massive metalminds be able to pound a mountain out of existence? I don't really know the physics, but something like tapping gold, steel, pewter, and iron should be able to combine them for massive bursts of destructive power. If you were to fold them into a single punch, wouldn't both the speed, momentum, and strength just obliterate something? (Like leaving a hole in a tower, causing it to fall) Now while they may not be able to literally destroy a mountain, they would be packing enough firepower to destroy a large building, which is pretty terrifying.

[cometaryorbit]

Destroying a building would be possible but impractical. It would take a ton of storage, because you'd have to tap at very high rates, but also keep it going long enough to hit different parts of the building - unless you could destroy one critical structure that brings the whole thing down.  What Wax does with Iron tapping and allomantic Steelpush is much more efficient.

A mountain probably wouldn't work, though. You couldn't store enough in a lifetime. Even a billion times strength wouldn't let a human destroy a mountain with bare hands - destroying a mountain would take a rather large nuclear explosion, which has much more than a billion times a punch's energy.

(The Sedan test, 100 kilotons, made a crater 320 feet deep and 1280 feet wide -- that's still significantly smaller than a mountain.)