Some Questions for Physics Junkies

[Norfindel]

The other factor to keep in mind here is that Marine suits are in all likelihood designed to keep them as balanced as possible. I would assume that the same technology that keeps Marines standing despite the ultra high recoil of their weapons would keep them standing here, too.

But that's just a guess, I know next to nothing about the physics at work. And I'm enjoying the discussion very much so keep at it.

In fact, the explanation in Legacy of the Xel'Naga is unnecessarily complicated. First of all, the armor adds a lot of mass to the wearer, damping recoil. Second, powered armor is likely to just sense the movement of the wearer. It doesn't needs to detect specific postures somehow and react to them. The armor wouldn't move by external forces as you didn't moved first, it will try to keep the same posture up to the strenght of the armor. It would be easier to detect the push of the trigger than the "shooting posture" anyways.

[solidsamurai]

In fact, the explanation in Legacy of the Xel'Naga is unnecessarily complicated. First of all, the armor adds a lot of mass to the wearer, damping recoil. Second, powered armor is likely to just sense the movement of the wearer. It doesn't needs to detect specific postures somehow and react to them. The armor wouldn't move by external forces as you didn't moved first, it will try to keep the same posture up to the strenght of the armor. It would be easier to detect the push of the trigger than the "shooting posture" anyways.

None of us said anything about computers demanding that a marine shoot in a certain posture.

It's easier to just rectify that all marines shoot in generally the same standing posture because that's how they can line up a shot with their holo-p and motion prediction. It's harder to aim at an outline drawn by a projector on your visor at the hip than when aiming; even if the outline is 2 inches ahead of your eyes (visors are wide; sorta like a planetarium) + plus it shrinks with distance - but other symbols help detail particularly far away outlined shapes)= even so, the naked eye makes a far away object look about the same size as another at a certain point; beyond that, a gun can still tell a marine where to shoot with very careful aiming - but such is a skill yet extends range up to 1 km and a 20 round burst is about the most damage you can get out while giving the same accuracy.

Motion prediction is a surprisingly simple system - it has a calibration, but it's usually tied to about 0.2 or so seconds (the time reflects a prediction into the future), since too far beyond that will mean that the laws of probability take over and the system's dynamic coding tends to often give out false target recommendations.

So, holo-p will outline a target based on what it can sense (holo-p uses several difference kinds of radiation such as radar, ladar and magnetometric - but none actually work against cloaking hence why they need triangulation from another more powerful source to detect a cloak). The general target's shape will then be read by the motion prediction program - the motion prediction program duplicate's the unit's shape and then places it at another position in space based on a variety of factors in another program's odometer (the program that calculates 'visible' target speed, velocity, and acceleration). If the shape does not change its space entirely (ie. an enemy moves an arm rather then it's entire body), then part of the shape of the moving body parts is outlined in another location but is less predictable - hence an enemy can still dodge a marine bullet if he anticipates the aim.

Particularly fast targets (like, 2000km/h or more) are also difficult to read on motion prediction. Alternatively, this is simply because the shape on holo-p actually moves too quickly.

A holo-p uses a scanner that is built into the suit as well - hence it works in any environment, provided a marine isn't completely surrounded by solid matter with an enemy on the other side.

Holo-p works through fog, but not through solid matter. A unit with cover also does not give out any shape read out (read outs are based on a database of known target shapes of various creatures and structures; a partial shape of, ie., a hydralisk, isn't one of these and is too varied to bother accounting for - all shapes are read by motion prediction, which then runs its appropriate routines based on the shape's 'physicality' - unknown shapes confuse the program and would actually cause it to slow down its output to the display, so unknown shapes are simply not accounted for by holo-p's initial display; of course, the 3-d scanner accounts for everything on the other hand - think Tony Stark 'Ironman' technology level), so hitting isn't gauranteed unless the unit is right in the open; also multiple rounds (as in, firing 100) is less accurate than one due to the time factor (firing 100 takes about 5 seconds on burst setting whereas it's about 1.5 seconds on full auto; the firing rate of burst setting is identical to the marine's attack rate in-game - in-game terms, I'd rule full auto is about double damage but then maybe there's a 2 - 8 second reload period; most rifles have 500 spikes per clip so the clip itself is quite heavy too).

So, motion prediction duplicate's a target outline provided by holo-p and then draws it out again in a different location and a different color so that the wearer can discern if one is the actual present location and the other is the 'future location' (or part of the original outline in a different location if some of the co-ordinates of the original are identical). The holo-p scans at a very high rate. Like thousands per second to accomodate ie., 1000 or 1000,000 million scans per compiled packet from which the motion prediction can make an accurate estimate when compared with the odometer; futuristic wi-fi helps with this - even though the naked eye is 60fps, the motion prediction displays at triple this because terran software engineers are paranoid that precision of the program is reduced if it outputs more slowly - also some super-human characters can thus take advantage of a suit too.

Smart marines can estimate a target's location and then are usually able to shoot through cover since gauss rifles can pierce pretty much any kind of armor (up to 2 inches of steel per round, so surmounting forces from several can crumple vehicle armor too!).

Dynamic coding produces dynamic AI. What is dynamic AI? It's better than what we have right now. It uses a degree of sentience which actually improves the AI's performance in some scenarios. Note that, ignoring pop sci fi nomenclature, sentience is not comparable to human intelligence (in the real world, we refer to that as 'sapience' AKA 'capable of producing, interpreting and reciprocating language and notions' - sentience merely indicates the ability to react to extant stimuli that isn't controlled in an environment (so in other words, cows have sentience but jelly fish probably don't).

Programs in real life aren't sentient at all, they constantly need to be adjusted with fresh code to accommodate their ability to talk with other extant programs (and the extants need the same treatment in turn). A sentient AI doesn't need this.

Terran don't have full out sapient AI's - the kind that you might find in star trek or Halo or AC Clarke (of course, said sci-fis probably erroneously refer to them as sentients; though I don't know about AC Clarke), in other words (AI's from those other series are basically human).

Sapient AI's, in application (and theory), are only possibly more efficient than dynamic AIs in the sense that they can re-introduce new theories and, if they figure it out, hack existing computer systems and even introduce new code as a result of what is essentially a human's capability to learn and invent things. Cortana did this once, and without formal schooling; none of the ability to hack was probably covered by her actual coding, but she was given greater IQ than humans and could thus probably even upgrade herself as long as her existing processors or whatever could cover all the new energy needed; note also that AIs in halo forge their own personalities and identities as well as socialize, but background routines - AKA brain washing for humans - are what keep them focused on tasks given to them and giving them a task usually just necessitates telling them to do so rather than coding it into them; a UNSC starship on a 6 month tour probably doesn't contain any software engineers on board.

This is all in order to basically make up for human incompetence (and inevitably usurp said humans). It results from socially degraded system of user friendliness rather than actual efficiency and job assuredness. Hence, terran, even with their (sometimes) lower-tech tools, are actually more efficient than the more corrupt UNSC. Terran, as a species, have the odd abundance of mad scientists that invent hardware way beyond its time (ie. defense matrixes and the gestalt program), but they are mostly founded in rugged but reliable utilities. After all (another halo reference, although perhaps it originated in starship troopers what with the 'why don't we just nuke them? all you have to do is push a button'), Mendez says that machines can break.

A variety of dynamic AI covers most of the nitty gritty terran software. Each has different 'instincts' which sometimes result in odd behavioral anomalies (spider mines would sometimes scrap amongst each other whenever they weren't on stand-by or burrowed in the ground and ready to blow up on a target that holo-p says is an unfriendly; from the wiki).
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Holo-p identifies friendlies and unfriendlies based on a GPS ordination system in the armor as well. Some marines also have mini-maps on their armor, that utilizes GPS. GPS identifies allies and friendlies as yellow and green respectively, while enemies are red (all displayed in the holo-p's initial outline of the same colors). It does this by reading the command channel's log (usually the one that is appropriated to be in that specific region; in other words, ie., if the confederate marine core orders a division of marines to travel to Korhal and occupy Korhal, then it would log the info in any satellites or probes or other GPS displays sent as equipment to aid said division, or multiple divisions, in their mission of occupying Korhal).

If an armor isn't connected to any command channel, then it is in high risk of friendly fire. Civilians are also not often connected to command channels and can be identified as enemies just as often - and we all know what that means.

Marines have thus often so much as delighted in shooting civilians whenever they're ordered not to necessarily ensure that said civilians remain alive (ignoring the matter can mean that civilians will and do die; even resocc marines do this, perhaps especially at times). The reason for the above is that having to ensure that civilians remain alive means, of course, making it more difficult to identify real enemies (since civilians are red anyway; unless a commander makes an effort to get every civilian added to his ally or division list - division list is green, ally is yellow). Usually yellow civilians are only result of said persons being escorted or designated VIPs.

Dead targets (those with no biometric-sig) are not shown at all. Dead enemies are more difficult to identify without a bio-metric scanner or actually physically going up to said target and using medical knowledge to determine if they're alive or dead (we have the latter technology in real life).

A bio-metric scanner is a powerful utility so armor does not have it - an admin dynamic AI (like the various adjutants) sometimes uses one to identify life forms but has to identify them on scale based on current scientific definitions of what is technically 'alive'. This is the only way to ensure enemies are dead and is often done after a nuclear strike.

Many marines aren't technicians and are confused by holo-p and its ability to confuse with many shapes that can disrupt actual vision. Hence, the dumber (yet more gung-ho, probably) marines throw up their visors. Suit software has to have its BIOS reprogrammed in order to change the settings on things like holo-p always being active, but the holo-p itself can be reconfigured. Still, not all marines are technicians. Since software remains active all the time unless its on stand-by (and stand-by cannot be controlled without proper technical knowledge), since a suit is always 'on' due to its cold fusion reactor's instability with having to give out energy. A suit will only power down when a cold fusion reactor or fuel is removed (the glowy stuff in that one cinematic is probably plutonium cores), which can be quite dangerous in itself. Suits are based largely on inflexible non-user friendly programs (except for their basic function) since its all part of an effort to make suits less vulnerable to sabotage.

Some squads carry along technicians - technicians are usually responsible for ECCM systems however. The systems themselves are provided by SCVs and are important for preventing CMC armor from getting hacked (some dynamic AI can make hacking a very quick process). Even so, CMC armor is quite difficult to hack - compare it to hacking into the BIOS of a PC in RL. Yes, it's not like getting into a server or even something more complicated like planting a virus or even designing a virus that whipes an entire OS clean.

ECCM itself is also sometimes referred to as 'electronic security system' or simply 'security system' and varies highly. The most reliable are very low tech - ie., they project digital white noise and interference and can create dead zones. Dead zones are completely immune to any sort of hacking known to man but can reveal an enemy's location - so, trade one for the other.

The armor wouldn't move by external forces as you didn't moved first, it will try to keep the same posture up to the strenght of the armor.

That would be rather uncomfortable, since I think the armor conforms to the body a bit (by that I mean, the inner layer that keeps the otherwise naked limbs attached to the suit's fingers, etc.).

In other words, parts of the suit, like torso and spine are immovable - but other parts are made to obey gravity to a degree. So when a marine falls down, the limbs aren't going to be stuck in the same position (that would make the marine look like a very heavy toy soldier) - instead the servos will fall back so that the legs meet with the body in their appropriate position. One of the most finesse parts of the entire servo system - besides the fingers (note that some suits allow naked fingers to fit into the actual glove finger slots but still use servos to move the fingers in reaction to potential energy from naked human motion; probably some old-blue models. Old-blue's were probably not all standard, unlike the dominion 'second war era' CMC-300s) - is most likely the groin region, since it allows legs to turn. The 'ankle portion' is less finesse and allows foot falls to angle vertically or horizontally at only a small degree (so the groin allows better control over foot falls than the actual ankle; the ankle portion is also covered up unlike the groin region in the new CMC-300 I think). The groin region might be less advanced or the same in old blue models (or maybe it allows actual hip movement unlike the new dominion models; I don't know).

[solidsamurai]

Regarding recoil.

The gun weighs about 40lbs. + magazine which itself is about 30lbs.

The recoil should be pretty low with that included. CMC allows firing with just one arm bearing the gun.

Also muzzle flash results from detonation, resulting from sudden electrical flow in the coils. It's a phenom of sudden photons and heat build up with each round. Note that fires are possible with very little oxygen - it's called 'plasma', most of the time. How does the sun's surface appear like fire in space, where there's no oxygen? How come the sun doesn't explode with each fusion reaction at its core? That's also why the detonation chamber itself doesn't rupture and explode and a container isn't necessarily needed for heat build up and a resulting explosion (a container only contributes to heat build up). In the case of a C-14, the build up is so quick that the space that the surmounting heat from the coils occupies doesn't occupy space quickly enough (heat has to move to occupy space; usually it does so via methods you can read about in any high school physics text) and the compressed heat explodes.

With the detonation, there's sudden excess heat that goes through the muzzle and the rest is gas that goes through a open/close slide at the side.

And 33KJ seems about right - maybe a little more. Maybe on a 5 - 10 MACH scale, I'd say 7.5 or MACH 8.

[Quirel]

Lol, I come into this thread expecting to help with a rather straightforward problem (Or non-straightforward, like how plasma coated bullets would work.) and this is already at a level beyond what I'm willing to contribute.

However,

On impact both bodies would travel at the speed of 4.05 km/h which would for sure take down the Marine if the Zergling leaps toward the head. If the 888.89 N force doesn't breaks the lower back of both the armor and the marine then the Zergling could start stabing.

If they have different mass, they won't travel at the same speed after a collision. Think about a truck vs motorcycle collision.

Sure, if we're considering a billiard ball colliding with a marble. But since we're talking about a Zergling colliding with a Marine, denting the armor, and latching on with razor-sharp claws, I think we can throw perfectly Newtonian constructs out the window.

If both bodies collide and combine, then momentum for the whole system will be conserved, and M1V1 plus M2V2 will equal M(total)V(total).

[solidsamurai]

If both bodies collide and combine, then momentum for the whole system will be conserved, and M1V1 plus M2V2 will equal M(total)V(total).

What's your basis for that claim?

You just said 'let's throw newtonian physics out the window'. Just... whoo! Throw it out.

And then you say that you wanna apply conservation of mass which relates to p = m*v - I believe that's the formula for momentum. If momentum is conserved, something else has to be conserved. So what's conserved? Mass? Volume?

Taking physics in school kinda helps you think about these things.

Sorry no offense or anything, but physics is hard. It's difficult to talk about anything physics without debunking claims and offending. 'Cause it's science, y'know? :P
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If you wanna be more open about things - let's look at it this way. I say that a zergling latches onto armor with its jaw and that it's claws aren't good enough to get through armor (it uses its talons; its talons are not its claws - they're the appendages above the claws, on the back, and they have these huge friggin scythey spikey things attached to them - I call them talons but the game might use the 'claw' convention; whatever). A zergling is strong (3 manpower), and it might use its jaw to help prevent a marine from getting it off. A zergling would also defeat a marine in an mma brawl, but a marine's armor allows some physicality elements such as its ability to probably punt a zergling or disorient it with its fists. The thing is, a zergling doesn't allow that. If a zergling is close, it reacts quickly by doing one thing - eating someone alive, rending them or just out right killing them somehow.

A zergling that hesistates was ordered to hesistate and is thus stupid and thus dead in the hands of any competent marine.

[Quirel]

What's your basis for that claim?

You just said 'let's throw newtonian physics out the window'. Just... whoo! Throw it out.

If you reread what I said, dear sir, I said "Perfectly Newtonian constructs."
As I understand it, a billiard table is a perfectly Newtonian construct, because the balls are not irregularly shaped and do not combine (ergo, an elastic collision). This is a scenario where the two objects will stick together and combine, hence it's a perfectly elastic collision)

And then you say that you wanna apply conservation of mass which relates to p = m*v - I believe that's the formula for momentum. If momentum is conserved, something else has to be conserved. So what's conserved? Mass? Volume?

Taking physics in school kinda helps you think about these things.

Yes, yes, taking a physics course and a calculus course in both high school and college has helped me think about these things.

What I mean, is that the momentum of the two objects we're considering here (A Terran Marine and a Zergling) will be conserved upon collision (Ignoring outside factors like friction, and assuming a head-on collision.) They will be moving together at the same speed after they hit each other.

p = m*v is the formula for momentum, yes. However, M1*V1 = M2*V2 is conservation of momentum, which means that momentum itself is conserved. Take the momentum of the Zergling and the momentum of the Marine and add it together. Now divide it by the combined mass of the Marine and the Zergling, and you have the velocity of the two traveling together after the collision.

Norfindle said that the Zergling and the Marine would be traveling at different speeds after the collision, and hence would fly apart. I was pointing out that it only works if the Marine and the Zergling collide like billiard balls. A Zergling is going to pounce and latch on, so a better model would be to consider the Terran Marine and the Zergling to be part of the same mass after they hit each other.

Have I repeated myself enough to get through to you, dear sir?

Sorry no offense or anything, but physics is hard. It's difficult to talk about anything physics without debunking claims and offending. 'Cause it's science, y'know? :P

Oh, I'm sorry. But it appears to me that you're the one who didn't know what conservation of momentum is, hein?

As for physics being hard... well, I found it rather easy*, with the exception of electromagnetism. To each his own.

*Before you jump on this, I'm talking about the material covered in semester-long high school course taught by someone whose serious about the material**, and a year-long course taught as a part of his transfer degree. Of course, we didn't get into really in-depth stuff, like you would with a specialized college course or a full degree, but Newtonian physics is HARDLY in-depth science.

**It doesn't quite matter who teaches the material as much as the person learning it. But a teacher who cares and a student who wants to learn beat out a disinterested teacher or a apathetic student any day of the weak.

[solidsamurai]

Kk fine, forgive me for accidentally taking you out of context.

Have I repeated myself enough to get through to you, dear sir?

You've repeated yourself effectively once. If you said it more than once in one post, then that's not my fault.
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BTW, don't call me 'dear sir', we aren't intellectuals smoking pipes here.
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I figured out the theoretical initial force provided by a gauss rifle's coils on each spike.

In order to do so, you have to consider impulse.

I went by the assumption that it takes .01 seconds for a gauss rifle's coils to pass current that results in a detonation inside some sort of chamber that can pass mechanical energy to the rounds (in turn resulting in kinetic energy thrown over to the rounds resulting from movement of the spikes, etc., etc.).

The number of joules and current needed + efficiency for the coils is undetermined (out of my league), but irregardless I figured that a spike typically travels at Mach 10 (in dry air of earth atmosphere at 20 degrees celsius of course). That's roughly 3433 m/s.

Hyper velocity is usually 7.2 mach minimum (from wiki). Also, wiki apparently says that objects can liquify on impact - evidence derived from meteorite and asteroid impacts (such objects move at hyper velocity). It didn't delve into explaining why the phenomenon was apparent - it did say though that liquifying a (normally) solid and dense surface (they actually referenced steel as an example) meant that the inertia of the object traveling at such velocity could take it through the surface almost un-hindered.
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To calculate impulse, the formula is: I = FcT

Where I is Impulse and FcT is the amount of force exerted over a certain time period (the time period is given as change in time; I used a 'c' to denote this since I can't type out delta symbols).

To get FcT, you need to consider mass * change in velocity. Velocity considers whatever object is moving in one direction (the 8mm spike in this case). From calculating all that, you get cP (change in momentum), which is what impulse is by wikipedia definition. From that formula though, I can consider the amount of force that is needed to be exerted to accelerate an 8mm spike (the gauss rifle article stated that each spike weighs about 33g).

So, I've already considered that velocity is 3433 m/s (close enough to reflect Mach 10). The article says that 8mm spikes are 33g per spike - in effect, .033 Kg.

We can assume that a marine aiming his rifle at a target 1km away (typical engagement range I'd say), can allow a spike to reach the target in 0.291 seconds.

The spike achieves it's velocity of 3433m/s say... .1 seconds (arbitrarily given, for logical reasons). For whatever reason, it does not accelerate beyond that and the momentum remains the same - after all, marines do 6 damage regardless of range in-game. Some principle prevents it from decelerating too - it could just be the inertia of the spike itself pushing against the drag of air resistance.

Calculating friction to determine the amount of heat this causes would be another matter (enough, and the round would light up as it travels towards the target - like some WW2 autocannons tend to do, don't they? Greater mass of a round lends greater friction and autocannons usually exceed 1 Cal.).
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So in other words, a C-14's spike should penetrate at maximum effectiveness at just less than 500 meters.

But what is muzzle velocity? Well, assuming a spike is already loaded into a barrel and then propelled right after 0.01 seconds - then we can assume that acceleration may be about 343.3 after just .01 seconds (acceleration = change in velocity divided by change in time - in this case; I just multiplied the maximum velocity by 10, since acceleration is in m/s).

In .01 seconds (the actual transfer of electrical energy from the coils is at light speed (or close to? At least, it's basically light speed relative to everything slower than it); so the time lapse of all that is infinitesimal), velocity should effectively be 343m/s. At this point, it's already traveled about 3.433 meters. That would be roughly equivalent to muzzle velocity.

11 Newtons of force (a spike is fixed and non rotating at this state - its net force prevents it from rotating; in fact, I think the term 'rifle' is just a catch phrase in the terran setting to denote 'any gun that shoots really far and is held in two hands' rather than 'having a rifled barrel that rotates a bullet to enhance inertia' or what have you), may not be much; but then again, the acceleration changes over time and so does the velocity - so, in .01 seconds - a zergling that is hit by 11 newtons of force at an 8mm wide section of its body is not going to be penetrated (I don't think 11 newtons on skin is enough to tear or penetrate, is it? Even skin flakes of 8mm are surprisingly tensile).

Also, chances are that the section of penetration is even smaller (unless the marine didn't make a 'straight shot') - note the denomination 'spike'. The very penetrating front end of the spike is much smaller than the width at its mid section. It could easily be 1/60th the width of 8mm or less. Even so! the entire spike is probably just composed of common wrought steel - 11N isn't enough to make even a micrometer of any sort of steel yield though I don't believe. Regardless, the 'soft' nature of the steel is probably meant to warp somewhat to enhance the damage potential of the entire spike - hence, why it might lend to exploding skulls (this is in addition to the shock wave created by the raw net force formulated from a hyper velocity spike's inertia).

The Break Down
Even if the zergling's carapace can bounce a spike off of it however - note how bounce physics work. They are the result of one surface yielding to an opposing object, and then repulsing when said surface yields to a certain point, thus creating elastic energy that is transferred to the opposing object; thus converted to kinetic energy applied to the opposing object, which takes it in another direction (usually the direction of the elastic energy imposed by the bounce surface). The time it takes for this energy transfer to occur, would probably be a bit more than .01 seconds. So, really, in the time that the spike travels roughly 3 meters - it can sit at stasis at a zergling's carapace.

Certainly it will 'slow down', but it's acceleration won't change, as the acceleration is actually increasing relative to the amount of tensile opposition provided by the zergling's carapace (related to density or hardness/toughness and all that other metallurgy jargon).

So, as the bullet sits at the zergling's carapace - probably exerting a force of about 11 newtons at a diametrical width of (maybe) 133 micrometers on a zergling's body (the width of the end of the nose of the 8mm spike), pretty much nothing happens. I consider even zergling carapace to be quite strong.

At 0.2 seconds, the spike presses against the zerg carapace. Acceleration has doubled - which lends to force. Note that acceleration may not have actually doubled - in fact the effective (max penetration) range of the gauss rifle may be increased due to having to pass through zerg carapace before it reaches max velocity. I'm assuming that it has doubled as a convenient way of calculating force - without trying to figure out all the energy conversions (a bullet that doesn't move as much has less kinetic energy even though it might have a lot of inertia moving it forward; so using kinetic energy for armor penetration doesn't really help in firearm physics I don't think).

Anyway... double acceleration would yield 686.6m/s at 0.02 time interval. Hence, the force driving the bullet is now 23 Newtons. This is what would be stressed against a zergling's carapace - and it would build! Note that since I've already assumed speed and calculated acceleration from that, we don't have to consider gravity - since acceleration assumes that it is enough force to overcome gravity (and hence any left over force is the 23 Newtons at the 0.02 second time interval). Air drag resulting in air friction that takes away from the over all force is not factored - as such, force can be calculated in its most simple formula - beyond 1km, the drag reduces speed, even if acceleration remains the same.

Now... lets fast forward to the fun parts - how many newtons does it take to penetrate zergling carapace? Well... steel in general, if it has a yield strength of 690 megapascals, requires .276MPa to create at least a 2-inch 8mm wide hole inside of it. The force of a steel spike, having traveled 1km - would be 3296.71 Newtons.

That is quite a bit obviously - since a pascal is essentially a force of 1 newton to a square meter. Rendered in 2 dimensions, we'd need a force of 55.2 Newtons. This probably isn't all that accurate.

But assuming acceleration of the spike does not continue past 'max velocity' and is effectively overcome by air resistance up to that point (thus maintaining the velocity of the spike until the momentum begins to lower)? The force is instead 1132.89 Newtons. Which is quite high - considering it can penetrate about 41 inches of steel - roughly a whole meter! No wonder gauss rifles can overcome tanks in-game.

Of course... a spike probably encounters dragging resistance from the steel - the collision with steel may cause the steel itself to liquify which might even expand the spike's penetration properties (not to mention the pointy end of the spike can get further in before the rest of the spike encounters drag). I'm going to assume, however, that the spike itself liquifies a bit as well. Maybe some inertia based principle retains some of its structure.

Regardless, the spike will no doubt expand (if liquification is related to heat) and become softer. Hence, it could do a lot more damage than a simple 8mm hole. Such damage wouldn't relate to the motion dynamics of a bullet's tendency to 'yaw' and 'pitch' and bounce around inside someone, but actually relate to shock waves created by incredible force in the first place. In other words, a spike's net force could displace air inside an individual's body. The force at which they are displaced overcomes each part's yield strength - hence, heads probably can explode (at least partially) from a single spike at shorter ranges.

This is because a spike ends up putting more pressure on a portion of the body when at lower acceleration - it's acceleration effectively increases in order to penetrate. Of course, this is all just theory.
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Anyway... surely even a zergling's ultra hard carapace would get displaced by a single spike. Hydralisks might have similar carapace that's thicker (reflecting the 1 armor value as opposed to 0) and more hp simply because they're bigger and have more energy driving them around town.

Hence, I propose that a zergling behaves the way it does (detailed in the above posts). A typical gauss rifle fires not one, but twenty spikes. If they all impact with a zergling, it could be done for - maybe it's incredible tenacity would allow it to remain alive but it would be wounded. In-game a zergling requires six bursts from a gauss rifle before it basically explodes. Judging by the mechanics of the gauss rifle, this seems to make a measure of sense. In fact, a zergling might have inner and outer chitin - it's bones protect it a little better from the internal bodily shock waves that C-14 spikes can create.

Regular non-gauss rifles might not penetrate at all (I'm going with the idea that zergling carapace is harder and tougher than steel), but if they did (by chance; zerg do have weak points) they may do similar damage due to yawing and bouncing and what have you.

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I think the theory about gauss spikes stands to state that 'maiming rounds' would be much more dense than regular 'kill rounds'. Kill rounds explode heads since steel spikes get softer at hyper velocity and can warp incredibly upon impact with similar tensile strength surfaces - while maiming rounds turn people into swiss cheese since they just go right through everything without warping (although they might displace air for shock waves - by chance that they exceed the speed of sound and 'sonic boom' inside somebody; I imagine C-14 impaler spikes are even more effective in areas where the speed of sound is higher, such as water).

Anyway... all of that is my current theory. I'm not sure if I correctly made the connection between impulse and over all force and what have you, though (in fact, I still don't know what stop a bullet from accelerating - it can't be gravity since it has to at least exceed that and friction is just some kind of percentage reduction).

Nvm - Force in Newtons is the amount needed to propel a mass a distance. So... if the force is 1132.89 Newtons - multiply that by the effective application to the mass of the bullet. You'd get a force that can propel 33 grams 34.33 km (this assumes that there's already some additional force overcoming gravity; no, it's not anti-gravity inertial stabilizers installed in the spike, sorry - just more driving force. The 1000+ newtons is the penetration force at the small amount of area.).

Beyond that, acceleration diminishes and gravity begins to take hold (what causes the fall off curve though?). Actually, I suppose acceleration would diminish beyond just 1km (more realistic?) - it may travel at very high velocity though until it reaches the 34.33km barrier. At 34.33km, accuracy may be considerably reduced and it may not be worth shooting at targets (such as aircraft) except to scare them (In 'uprising', marines probably did that to the 70km or so distance aircraft; aircraft in SC probably have optics that allow very high magnitude viewing and marines tend to like to make their presence known, as part of ressoced war discipline, rather than keep quite at all times).
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The C-14 Impaler Gauss Rifle Break Down

- Max penetration is achieved at up to 1km. It can't always penetrate through a 1km line of targets since the 'max penetration range' value diminishes per target that it has to pass through. Beyond that, there's less force driving the round forward. Maybe this is why marines only fire upon targets uncovered by fog of war. In SC 2, bunkers increase their range probably because bunkers just make aiming easier at a psychological stand point (or due to that technology in single player).

Please blatantly and snobbishly correct me if I'm wrong on any (or all) of this.

[solidsamurai]

Up next is the momentum. Momentum is important because it tells us how much recoil a weapon will have. Many mistakenly think that kinetic energy is what's behind recoil, but that's not the case. According to the conservation laws, kinetic energy is not conserved, but momentum is. In other words, just because the C-14 has the same amount of kinetic energy as a .50 cal machine gun, doesn't mean it has the same recoil. As for specific figures, we find that the C-14 has a recoil between 18 and 40 kg*m/s. For comparison, a .50 cal machine gun has a recoil between 39 kg*m/s and 46 kg*m/s. That’s a pretty substantial difference, only the highest figure from the C-14 matches the lowest figures from the .50 cal machine gun. But, that's still a very significant recoil, far greater then what you'd get from a modern assault rifle.

If you want to get recoil by conservation law - use momentum of round + momentum of energy needed to propel the round in the first place (for that you need the velocity of the round times the mass of any effective thrust created. In other words, the mass of force used during the impulse phase.).

Divide the sum by the weight of the weapon + weight of whatever is holding onto the weapon. That's effectively how much force a person would need to retain aim (or to prevent themselves from letting go of the gun, or letting the gun move them - the latter applies if the force of the recoil is enough to actually overcome the net force of their own body I believe) - from that, we can gauge whether or not a person without CMC would be able to fire a gauss rifle (also note that a person not wearing CMC is certainly less massive).

Free recoil, on the other hand, is characterized by a 'back draft' I think (instead of the kick of the weapon). It might not factor in bodily weight, because of that.