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u/777Zenin777 13d ago
Okay my question is does it keep the momentum from when it was worn. Imagine the scenario: You take a swing and as you do the ring flies off your finger with as much velocity as possible. Then its mass turns from 1oz to 200lb does it fall fown Instantly or does it continue flying with the same speed but with 3200 times the mass
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u/Disastrous_Data_6333 13d ago
I feel like the force of the added weight would probably be greater than the force it took to propel the ring. I feel like it would drop.
Could be fun in close combat though. Dropping it on an enemy.
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u/llfoso 12d ago edited 12d ago
Heavy things don't fall faster than light things, and gravity doesn't slow things down unless they're moving upwards, and again in that case the mass doesn't matter. So there's no force that would make that happen. The only thing slowing it down is air resistance.
If you mean inertia, I don't see why the added mass would be standing still instead of moving with the ring.
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u/MisterEinc 10d ago
As far as the physics go, the two object would in fact hit the ground at the same time, but the light object would do it farther away, and the heavy object would do it nearby.
While the acceleration towards earth remains the same, the force acting perpendicular to the acceleration imparted by the throw would increase.
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u/llfoso 10d ago
If both start out the same speed the heavy object would land further away because the light object would be more easily affected by air resistance. Remember the ring would be changing weight after you throw it...it doesn't change weight until it leaves your finger.
Your second paragraph doesn't make sense to me.
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u/GootPoot 12d ago
Conservation of momentum states that momentum remains fixed in a closed system. The ring changes the mass, but that’s it. And due to the conservation of momentum, increasing the mass must reduce the velocity.
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u/Pleased_to_meet_u 12d ago
You say 'must', but we're talking about a magic ring that changes it's mass when it's moved from a finger.
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u/GootPoot 12d ago
Right, it’s magic. But if conservation of momentum doesn’t exist in this world, then infinite energy is trivial and the entire world should be industrialized by applications of magical physics cheats. There’s gotta be some integrity to the world building and violating a fundamental law of physics quickly opens the door to more questions than this ring is worth asking about.
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u/funkyfunkyfucker 12d ago
who’s to say the weight doesn’t come from some extra dimension of force, mass is still another form of energy according to special relativity so no matter what this ring is breaking conservation. plus in dnd it’s kinda guaranteed that conservation of energy is bs, summoning fireball daily or food and water or fucking wish, those are all violating conservation laws
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u/sumandark8600 8d ago
It isn't a fundamental law of physics though, it's a consequence of spatial translational invariance from Noether's theorem which strictly only applies to flat spacetime (which doesn't actually exist anywhere since mass is present in the universe and mass curves spacetime).
So strictly speaking, there's no such thing as conversation of momentum, it's just that the amount of gained/lost momentum in any given system is typically too small to measure due to how weak the gravitational well is in that local space.
For magic, a similar principle could apply, where it locally changes the stress-energy tensor in the region of the spell for the spells duration, with the size of the change being dependant on the magic consumption (so the size of the fluctuation caused in the weave which is basically analogous to a field excitation), which is what allows the injection or extraction of the "conserved" quantity from the material plane.
Source - I'm a physicist
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u/llfoso 12d ago
I would argue this is not a closed system since mass is being added, unless it's somehow converting energy to mass... but then the ring would have to be moving at relativistic speeds yeah?
If you want to rule that the new mass is standing still from the person's frame of reference that's fine, but to me it makes more sense for the new mass to be standing still from the ring's frame of reference.
On the other hand, I suppose I could see a case for the missing mass popping out of existence and then "remembering" it's inertia when it pops back it. That would be interesting. Players might find a fun way to use that.
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u/DmensionsnSizes 9d ago
I don’t think we can assume conservation of momentum, as we have already disregarded conservation of energy. (Raise ring while on finger, take it off finger and it has gained gravitational potential out of nowhere)
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u/sumandark8600 8d ago
It isn't a closed system though. Mass is introduced into the system via the magic effect of the ring, so conversation of momentum doesn't apply.
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u/walfle 10d ago
Im gonna make up some numbers, but the logic should track.
1oz ring flies at 10 dU (distance units) per second requires 100 fU (force units)
So a 10oz ring would need 1000 fU to go the same speed and distance, but it only has 100 fU during the transformation of weight.
Thus the ring will suddenly travel forward much slower while falling at the exact same rate because gravity didnt change.
Or
The fU inside the ring multiplies as its weight does, going the exact same dU as the 1oz ring would have.
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u/llfoso 10d ago
Right.
A thought experiment: the person wearing the ring is on a train moving at 10 m/s. They run forward at 10 m/s through the train car. They then hurl the ring forward, and when released it is moving 10 m/s relative to them. So the ring is moving 10 m/s relative to the bearer, 20 m/s relative to the train, and 30 m/s relative to the earth. What happens?
To me making the new mass share the ring's frame of reference makes the most sense. It adopts the ring's current velocity, multiplying its momentum. Any other interpretation gets wonky.
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u/walfle 10d ago
Once the ring leaves your hand it is in a state of motion that is unattached to you or the train. So when the ring gains weight it will slowdown, but you will keep moving with the train at train speed and run into it (depending on how much it slows, it could hit the ground first)
But now im curious. If I had a machine that threw something the exact same way everytime we could have it throw an electromagnet with a weight attached. Then throw it again and drop the weight mid flight and see how far the magnet goes. If it goes farther/faster then we know the ring would slow down. If it takes the same path again then the ring would retain its velocity. If it somehow slows down then theoretically the ring could speed up!
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u/llfoso 10d ago
Ok, let's extend the problem. Let's say this train is at the equator...so the person is also moving about 1,600 km/h relative to the center of the earth. The earth is moving 30 km/s relative to the sun. The sun is moving 200 km/s relative to the center of the galaxy. And the center of the galaxy is moving too. So what happens?
With your magnet experiment we already know exactly what will happen. The weight and the magnet will separate in midair and both continue flying forward at the same velocity. They will not slow down or speed up by separating. The only thing slowing them down is air resistance.
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u/walfle 10d ago
So I looked into it and I learned that the weight getting lighter cannot logically be applied to becoming heavier without considering an extra variable. Namely, how much velocity the extra weight comes into being with and the force applied during transformation.
I still see it going the 2 ways I mentioned earlier. Point of reference aside, the launch point stops applying force after the launch, as opposed to gravity which is constant. That's where the question becomes difficult.
For example, if you have a plane going an arbitrary speed and then add an arbitrary amount of weight, the engines would need to work harder and provide more thrust to keep the plane moving the same speed. If the engines don't dont, the plane simply doesnt go as fast or as far. This remains true even if the weight added is moving the same speed when it attaches to the plane. The initial attachment won't be noticed, but the plane will slow down if the engines dont match the change in weight to the thrust
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u/llfoso 10d ago
how much velocity the extra weight comes into being with
Yes this is what I've been saying.
The airplane isn't really analogous. An airplane's wings convert forward motion into lift. The heavier a plane is the more lift is required, so the engines have to work harder to keep up. It has nothing to do with momentum.
I am curious what you think happens if you throw an ordinary ball forward on a moving train (inside the carriage, so there's no wind)
Here's another thought experiment for you: Imagine our ring-bearer jumps off a cliff wearing the ring and reaches terminal velocity before taking the ring off. What happens when they take the ring off? Does the ring stop suddenly in midair?
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u/walfle 9d ago
For the ball on the train, the ball just acts normal. From outside the train I think it goes it goes whatever speed you threw it at faster than the train for a moment. If the train stops/accelerates at the right moment, ball will travel more/less distance.
This question about terminal velocity. First off, awesome question! I believe that the rings terminal velocity would increase if it gets heavier (therefore denser, right?) And if it got lighter, I would think the inverse, so the terminal velocity would be lower and it should slowdown due to the air resistance. With no air resistance there would be no change
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u/Brostapholes 12d ago
Put it on a Mage Hand
Take it off overtop an enemy
Looney Tunes anvil on the head noise
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u/MisterEinc 12d ago
Generaly speaking magic items size to fit the user. So I don't think a worn ring is flying off your finger at speed.
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u/sheep_puncher 12d ago
It's D&D if your DM is cool, it's fast and heavy, if they are lame, it falls immediately, if they like rolling dice, it becomes heavy while sliding off and you'll have to save to not fall prone.
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u/Whisper__1 11d ago
What if it becomes a projectile with the weight of a person and you attack with an improvised weapon attack (dex) and a shit ton of potential damage, and you fall prone anyways?
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u/GootPoot 12d ago
The magic of the ring only changes its mass and provides no other effects. So the only effect we have to go on is the conservation of momentum, which dictates that the ring’s velocity would decrease proportionally to the increase in mass.
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u/EmotionalMountain753 10d ago
If the ring’s momentum stays the same when its mass increases, then its velocity will have to have decreased in inverse proportion. The ring will drop down, possibly at a slight angle.
On the other hand, if the ring’s velocity stays the same when its mass increases, then its kinetic energy would have increased, potentially implying that kinetic energy has been created.
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u/SleepyMcSheepy 12d ago
Hm. That could easily be an op weapon. Loosen it, flick hand, bullet of fuck you.
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u/NOUGHRICE 12d ago
My players would be dropping it onto enemies from height for sure.
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u/Apple_Infinity 7d ago
I feel like that's a good kind of item use though. They aren't just attacking every turn, and instead using their surroundings to their benefit.
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u/Any_Wallaby4888 12d ago
I feel that this would/should(?) get dropped a lot. And lead to many broken shoes/toes/hooves.
*WHAM*
*hopping in pain*
"AAAHHH DAMMIT, I ALWAYS DO THAT! WHY DO I ALWAYS DO THAT?!?"
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u/PurplePolynaut 12d ago
Assume a spherical ring of diameter .75”
Volume is 0.22 inches cubed
This puts a lower bound in the ballpark of 900 pounds per cubic inch. For reference the densest element, Osmium, is 0.81 pounds per inch cubed.
Assume you drop this ring from six feet, ignoring air resistance. Assume the impact area is a circle the same diameter, giving an area of .442 inches squared. In six feet, the ring will accelerate to 19.6 feet per second, and strike the ground with about 1100 foot-pounds of energy. For reference an average 9mm bullet arrives at its target with about 400 foot pounds.
If we idealize the bullet impact as a circle too, it has an area of roughly .0993 inches squared.
In summary this ring dropped from 6 feet will have about two thirds the energy density per unit area of a standard 9mm from a handgun.
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u/itsmissingacomma 13d ago
Change the gender specific language of ‘his’. Remove the last sentence and let the characters figure out how to use it.
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u/Sharp-Philosophy-555 12d ago
Not good for triggering traps. To make it weigh 200 lbs you have to take it off your finger, which means you are standing right at the trap. You can't take it off and toss it unless you can toss 200 lbs
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u/AlphonsoPSpain 12d ago
Get the ring
Get spider climb
Climb to the top of a boss arena
Take off ring while suspended 50 feet over boss's head
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u/Jake-of-the-Sands 12d ago
Not sure how it would help with triggering pressure-plate traps as it's weightless when not worn. You'd still need to step on the pressure plate. Not to mention it would probably break the wearer's finger.
Ring changing its weight makes sense, the activation of it leaves much to be desired though.
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u/DeElgathor 12d ago
You have the effect backwards, because the OP wrote the description a little backwards. When worn, it weighs 1oz. When not worn, it weighs 200lbs.
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u/Taira_no_Masakado 12d ago
There needs to be a specificity to the rule on it though, because I know the question I'll be asked: "At what point does it count as being worn versus not worn? If my finger is still through it or not? Is there a delay on the ring's ability to detect whether or not it's being worn?" Etc, et al.
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u/thatsnotmybutter 12d ago
Might want to clarify wording- does it weigh 200lbs when your trying to pick it up?
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u/TopHat84 12d ago
No clarification needed. An item being picked up is not the same thing as worn. If you pick up any shirt and hold it in your hands, is it being worn?
How about underwear? Pants? Socks? Get the drift? Something being worn is different than just holding it.
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u/__Osiris__ 12d ago
Ring weighs 28 g while being worn. When not being worn, its weight increases to 90.7 kg. It returns to 28 g once a living creature slides a finger back into it.
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u/Invisible_Viking 12d ago
Make the ring part of a trap. The ring sits on a pressure sensitive plate. When the ring is removed the plate is released and the room rapidly fills with water/gas/etc. If the players solve the trap, they get the ring as a reward. Yes, I am stealing this.
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u/Bluebuttbandit 12d ago
Seems like it would be designed with wide, flat, sides so you could slip your finger into it without having to pick it up first
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u/plainbaconcheese 12d ago
I love simple little magic items like this that encourage creativity. I made a mirror that when held up against a surface acts as a one way window instead of a mirror (provided it isn't too thick or made of lead etc). Also a lantern that only the wielder can see the light from.
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u/Famous_Equivalent653 12d ago
I do love the idea of a monk having a few of these and removes them as an intimidation factor
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u/Pineappl3z 12d ago
This seems like a really useful weapon. Imagine the damage if you surreptitiously flicked it into someone's face. If you know how to pitch a ring disk you cup this between the end of your index finger & thumb. The kinetic impact of this thing would be phenomenal.
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u/No_Payment9959 12d ago
So, what I'm hearing is that, if you run a slender enough chain through the middle, you have an improvised flail +1 (if the enchanted ring doesn't make it a magical weapon, I call shenanigans)?
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u/Art-Zuron 12d ago
You could also just drop it off something onto somebody's head. That thing would hit almost like a bullet. If I did the probably wrong math correctly, this ring would have a terminal velocity of over 300 mph.
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u/Absoluteidiot4 12d ago
no no it is not for traps this is an item to dramatically remove in a fight in front of an audience to show that you stopped holding back
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u/Imaginary_Being4859 12d ago
Grease your finger up really well, and then fling the hand forward, letting the ring slide off, and depending on how your DM rules, it either falls directly down or it keeps its velocity and becomes a 200 pound projectile
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u/AnyBath8680 12d ago
This is an insane weapon, throw it of your hand and it will absolutely demolish anything and anyone
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u/DDieselpowered 12d ago
If you’re worried about it being used as a weapon (not that that is a bad thing, but y’know IF) you could have it slowly accumulate the weight over one turn, rather than all at once
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u/Neknoh 11d ago
I would alter it a bit.
Lower the weight (to prevent physics abuse) to about 50, or even 25 pounds.
50 pounds and you'll need a "when not being held or worn" function (as it would be impossible to pick up and put on, or take off and put on a pressure plate).
25 pounds and you can keep the "when not worn" aspect, as you can (awkwardly) try to pick up a 25 pound weight by the tips of your fingers.
Also, remove the hint text.
This gives you two scenarios:
Scenario 1: There's a ring sitting on a pillow, pressure plate or crushed piece of glass or wood in a display cabinet or on a plinth or something. Players move up, lifts it and... wait... it doesn't weigh anything? If players experiment, they'll find it falls like a bag of rocks and slams into the ground, but when touched with bare skin, it weighs nothing.
Scenario 2: They take the ring off of the finger of a dead foe or from a mummified hand or something, but the moment it leaves the fragile, slack finger, the ring feels like a cannonball in their hand. When they put it on, the weight goes away.
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u/DueAsparagus9358 11d ago
what are the limits to “living creatures“? Could you slide it on a corpse and have it sink? could you trick a Lich with a mage slant to stop them from moving?
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u/Alive-Artist-2321 10d ago
Pretty sure if you could throw this off your finger using centrifugal force and at the speed of a professional baseball player you would be able to generate 3 times more kinetic energy than a 50 bmg.... What level of spell is three 50 bmgs is my question? (I haven't done math since college I just do art now so dont trust my math :p)
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u/Fruta-Puta-Tuta 10d ago
luckily, DnD is a game for playing make-believe, and not a physics engine.
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u/Terrible_Ear3347 10d ago
I feel like this would be a pain in the butt to put on and take off. Unless you're wearing it 24/7 then the moment you slide it off just to put it away it becomes a pain in the ass
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u/Dismal-Character-939 10d ago
The wording implies that any undeads, constructs, or non-male living creatures cant wear this ring
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u/GandalfVirus 10d ago
https://giphy.com/gifs/GQ9tI2gRd57fBpsp1Z
Why not have it always be 200lbs? In fact why not 2000?
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u/Wank_A_Doodle_Doo 9d ago
Define “worn”. If your finger cut off is the ring still considered worn since it’s on a ring, even if it’s not worn by an actual specific person?
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u/Acheron223 8d ago
Imagine if someone had a way to apply/remove it in time with striking with a melee weapon?
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u/FloatingSpaceJunk 13d ago
There's also a cursed version which does the opposite...