Throwing soft things, Baby through a car redux. Options

[Larme]

Ok, I was reconsidering the conversation a while back about a throwing adept being able to throw something soft, like a baby, through something hard, like an armored vehicle. People (who I suspect have little if any more physics education than me) were telling me that it's only mass and velocity that matters. But I know that can't be true. If I drop a canonball and a jello-mold of equal mass off of a tower, both fall at the same acceleration and should have the same velocity when they get to the bottom. Ignoring the wind resistance of the larger volume jell-o, we know what will happen: the cannonball will make a big divot in the pavement, and the jell-o will go SPLAT everywhere. Same mass, same velocity, less destruction.

Can someone help me understand what physical properties are at work here? I have a feeling it has something to do with the material's hardness. When the pavement has its equal and opposite reaction against the cannonball, the cannonball is fine, and this lets it penetrate further, right? It is able to exert 100% of its force against the pavement without being harmed, so it goes exactly as far as its mass and velocity would suggest according to your basic high school physics. But your jell-o takes only a tiny amount of force to destroy. When it hits the pavement, the opposite reaction of the pavement destroys the jell-o, preventing it from transferring all of its force to the pavement. Am I on the right track? Or is there something with the hardness of the materials - the equal and opposite reaction of the cannonball is enough to crunch the pavement because the cannonball is harder, but the softness of the jello means that, outside of ridiculous scenarios with a sub-light jello accelerator, it will never penetrate?

And what does this mean for a throwing adept? Should a GM let someone with missile mastery throw a muffin through an engine block? After all, the examples they give in the book of what a missile mastery person can throw are hard things. They don't say that ordinary things become weapons in the adept's hands "such as muffins, hotdogs, and boogers." It's magic, but there's a limit to what magic can do, right?

[Stahlseele]

if you let it drop from the tower to the ground, the ground is massive, there is no way to penetrate, the cannon ball won't penetrate either . . it will make a DENT and nothing more . .
drop both of those onto a wooden plate and both will probably penetrate . . start with a sheet of paper and go up, you can go for a while before the jello decides to go splat again

[Larme]

Ok, but why? What physical property are we talking about here? Is it really hardness, or is it something else? And why does hardness have the effect it has?

[CanRay]

Elasticity?

Wait, why am I commenting? I failed Physics... Well, more lost interest when I found out you could no longer order Weapons-Grade Radioactives off the Internet...

[hobgoblin]

reminds me of the thawed vs frozen chicken myth that had the mythbusters going back and forth until they found that a frozen one goes thru more layers of glass then a thawed one.

i guess it has something with mass vs its ability to spread out on impact. somewhat similar to why tanks needs threads or similar large surfaces to spread out its weight to not sink into the ground. hardness, rigidity, i dont know the proper term for it...

[CanRay]

Displacement.

The tank thing reminded me.

Better physics knowledge through being a gun nut!

[Stahlseele]

because deforming takes up energy which is used for further movement through the obstale in hard materials

[Daier Mune]

both cannonball and jell-o will strike the pavement with the same ammount of kinetic energy. however, the cannonbal,l being of higher density, will be able to retain its shape long enough to deliver more of its kenetic energy to a small area. the jell-o, being softer, will begin to deform and flatten out, spreading the energy out over a larger area and dispersing the kinetic energy.

another way to look at this is the difference between the standard bullets and the gel rounds. the gel round will hit with the same speed and mass as a bullet, but the gel round is soft and deformable, so its kinetic energy is transfered as a non-lethal wall of force that will knock you down, instead of the regular bullet's point of force that will punch through your flesh.

as far as throwing adepts? not sure. i guess that "its magic", and it's up to the GM as to how much physics and magic interact with each other. personally? i'd go with a slightly more physics inclined rule, and say that the improvised throwing weapons would have to at least distantly resemble dangerous objects.

[hobgoblin]

hmm, checking the text i see that missile mastery have gotten one hell of a power boost.

in SR3 and earlier, only sharp/pointy objects did physical damage, blunt items didnt.

but with SR4, everything can do physcial damage.

[ludomastro]

both cannonball and jell-o will strike the pavement with the same ammount of kinetic energy. however, the cannonbal,l being of higher density, will be able to retain its shape long enough to deliver more of its kenetic energy to a small area. the jell-o, being softer, will begin to deform and flatten out, spreading the energy out over a larger area and dispersing the kinetic energy.

Emphasis mine.

Density - and it's cousin elasticity - are the keys here. Since I can't improve on this post, I heartily second it.


From a rules perspective I would argue that anything with an object resistance less than the target can't penetrate it. If that seems too harsh, I would treat the difference as either extra armor or an AP value.

[Larme]

@Daier: Thanks! That makes perfect sense to me. I knew it was something fairly simple, I just couldn't figure out how it fit into the basic physics I already knew.

So, revisiting the baby thing--it would take a lot more velocity for a baby to go through a brick wall than for a steel weight, because babies are less dense and more elastic, thus they will deform on impact and spread out their kinetic energy. I wonder if anyone is bored enough who also knows the equations to figure out how fast you'd need to throw the baby?

[Shrike30]

I'd use Structure (essentially Durability), rather than Object Resistance (which has to do with how highly processed the material is).

Density and hardness are what you need to penetrate things. Depleted uranium rounds for cannon manage to be both very dense and "self-sharpening", which essentially means that it shears apart in such a way while going through armor that it retains a penetrating shape. Jello does not retain a penetrating shape when it hits something... it deforms immediately, and that deformation wastes energy (Daier Mune got into this). Some bullets take advantage of this... a hollow point deforms to "waste" energy inside of a soft target (like a body), allowing it to use all of the energy inside of the body rather than having the slug exit out the other side (and take all the remaining energy with it, inflicting less damage overall). Against the side of a tank, Jello doing a few thousand feet per second (and somehow not flying apart just because of the air resistance it's encountering) is going to make a very loud splat, startle the guys inside, and probably turn the Jello into fruit-scented steam as that energy converts to a less useful format.

There's a point at which kinetic energy and momentum *are* really the most important features of something hitting something else... if you got a pound of Jello up into space, up to orbital velocities, and then had it slam into a space station at a relative velocity of several hundred kilometers per second, the amount of damage would be catastrophic. I'm pretty sure missile masters don't get quite this scary, however.

[Stahlseele]

why do i not worry about this being the SECOND discussion dealing with babies being thrown through hard things?
oh, right, because i don't like children . . only if they are seasoned right *g*

by the way, anybody have the link to the original discussion? ^^

[hobgoblin]

problem is that the orbital jello would probably vaporize on re-entry...

[masterofm]

Unless you take MAGIC into the equation. Magic just throws physics out the window. When you throw the baby you actually increase it's density for as far as you can throw it for no apparent reason except for the fact that it's magic.

Remember when you take anything and apply it to magic you get magic and a whole bunch of sense that doesn't apply to it.

[Mordinvan]

Ya, your right, cause the idea of self-sharpening armor piercing babies really doesn't make that much sense anyway. But if you straightened them out, and got them to point their toes you could almost turn them into long rod penetrators.... Save a few (IMG:style_emoticons/default/nuyen.gif) and much lower availability over the regular APDS rounds.

[masterofm]

Although it is forbidden tech.

[Larme]

Unless you take MAGIC into the equation. Magic just throws physics out the window. When you throw the baby you actually increase it's density for as far as you can throw it for no apparent reason except for the fact that it's magic.

Remember when you take anything and apply it to magic you get magic and a whole bunch of sense that doesn't apply to it.

I think the crux of it is: how much can magic really accomplish? I don't think that missile mastery can be unlimited. It says that ordinary objects become throwing weapons. If someone wanted to throw a fork, hell yeah! But a pat of butter? Give me a break. This is not some ultra powerful drain-causing ultra magic. It's one power point. It turns relatively hard or sharp objects like coins or pens or pebbles into deadly weapons. But I think that GM discretion intervenes where someone wants to use something soft, like a cheeseburger, to kill someone.

[Stahlseele]

throw it in such a way that it gets stuck in his windpipe . .

[masterofm]

Well a baby technically isn't an object (unless it's already dead.) I would as a GM say no dice if someone wanted to fling a live baby through a wall, but a dead baby would work. Also a slice of American cheese would also be an object so I would even rule that as harmful. Also if a troll wanted to throw a dwarf with power throw it wouldn't work as the dwarf is a human and not an object (unless the dwarf was also dead.)

Hey a babies skull is pretty hard why doesn't that count? Huh? HUH? HUH??!!11!!!one!!11

Magic breaks all kinds of stuff. I mean look at gliding for lords sake. Someone can run across a peace of floss w/o it breaking, and your saying that if someone whipped a pad of butter that the magic wouldn't kick in and make it kill someone? It's MAGIC baby!

[Larme]

My point is that it would take some costly, powerful magic to turn a booger into a deadly weapon. A pen already has enough density and a low enough elasticity that it could hurt someone, the magic just gives it an extra boost. But snot does not, the magic wouldn't just boost it, it would have to fundamentally change the snot's nature. We're talking one power point. Magic is never unlimited. Especially not magic that's always active, has no drain, in fact no disadvantage at all and can't be dispelled or removed short of using a background count.

Also, you can't explain power throw as putting magic into the booger and making the booger powerful. The one consistent rule of SR magic is that ranged weapons cannot be enchanted in any way. Once they leave you, all the magic you have in yourself is no longer in them. Power throw enhances the person, and does nothing for the missile they use. Power throw lets something potentially dangerous become deadly thanks to supernatural enhancements to the thrower. It doesn't let harmless things become deadly IMO.

[CanRay]

OK, we've combined physics, magic, and improvised throwing babies as weapons.

Only on the Intratubez!

[pbangarth]

When you jump out of a rowboat into the water, it is a soft landing and you have fun. When you jump off the Golden Gate Bridge, your speed at collision with the water is such that the water doesn't have time to move out of the way, and you hit something that reacts like concrete. That's not so much fun.

The same applies when fast water hits something, hence the water jets that can carve steel. presumably, fast jello would do the same. Hurling a bucket of water or jello would encounter the problem of air friction dispersing the liquid pretty quickly. An aerodynamic, semi-solid object like a baby would reduce the effects of air friction on the way to the target. Whether you could achieve a speed fast enough to penetrate steel without air friction igniting/shearing the baby is a difficult question to resolve.

Hmmm... calling down a flaming, meteoric baby-strike on the enemy armor. Scary stuff.

[JeffSz]

Consider this: the flesh on the blade of your hand is soft. Yet somehow martial arts masters can smash through boards and concrete blocks (that have vacant space behind them - this is the key i believe. if there's space for the harder material to be displaced to, it will yield.)

[masterofm]

I see where your going Larme, but a baby would hurt a lot more then a pen if it was thrown at you with all of someone's might. Babies have bone and.... stuff.... and other stuff... in them. Now if you threw a baby at a steel grate the amount of body and armor that the wall would have would actually end up just soaking the power throw anyways. A playing card can cut threw carrots and human skin. If you brained someone with a baby flying at insane speeds whats not to say that it couldn't actually kill you if moving fast enough. I mean that is like 6 1/2 - 12 pounds of baby flying at you and if hit on the head it might be able to crack your skull.

oh yeah..... and MAGIC. A magic 1 mage can still summon spirits. A 1 PP adept ability can allow you to do stuff like run on a nearly broken tree branch, or kill someone with a coin, or an ice cube. I mean when you think about how movement works and all of that I mean why bother? Why not just shrug, and give up. Its magic.

The End.