Topic: Magic and Physics

[Marc R]

It would take a slick archer to still hit you, you could possibly tie a 1 pound oil soaked rag to an arrow, set it on fire, and launch it a short distance. . . .but if the archer were unprepared for it, I can't see them hitting something. . . then again, if you failed your RR and had what felt like a 1.15 pound arrow in your hand, you might drop it for a fresh one. . . crossbow might just feel like somone was pressing it down with their finger, or the archer was tired. . .they might not "get it" until after they pulled the trigger. . . .

Then again, it doesn't make the arrow heavier, it doesn't pull the object in that direction, it just pushes against it away from moving in the direction indicated. . .the "float" thing above wouldn't work all that well. probably the one reason this would actually really screw up an arrow is that arrows tend to spin and wobble a bit in flight, and this would definitely throw off the shot. . .but I'm not sure by how much, and the archer would still get an RR. . ."Away" might work. . .I'm not sure. . .have them pull the calculators. . .If a .15 pound arrow is pushed to 120 F/S then it's:

(simplifying, and assuming no other drag or gravitational factors matter.)

0.15 x 120 f/s = 18 fp/s

1 pound back toward the archer is

1 x 32 f/s = 32 fp/s

so that would mean

18 fp/s / 32 fp/s = 0.5625 seconds to reach 0 f/s

I think that's right, I could be mistaken. . . .that's cutting it pretty tight, a crossbow bolt can go pretty far in 0.5625 seconds. .

120 F/s x 0.5625 = 67.5 (Which is a gross approximation to avoid figuring out the curve of velocity change vs time and how that translates into a total distance.)

So it might not be all that good an idea if you're standing too close. . .

That's a lot of hand waving away details, or other issues like "Would the preference NOT to travel forward cause the arrow to veer off, and once turned, actually wildly change direction."

Even the basic math is probably not worth doing at the table, much less hardcore physics thinking on it to the point of covering all the odd angles. . . it's an interesting discussion topic, but it might be too much figuring to do when actually playing. ("Stop, let me figure the velocity conflict in this arrow before resolving the attack." might lead to your players beaning you with dice.)

[edxs]

(Which is a gross approximation to avoid figuring out the curve of velocity change vs time and how that translates into a total distance.)

Just use the 1-d position formula, x = x0 + v0*t + 0.5*a0*t^2.

Anyway, using 120fps for a bow, and 250fps for a crossbow, 1 lbf would stop the arrow in 0.56s/34' and the bolt in 1.17s/146'. Could be quite useful.

[markc]

 Hay I am looking for a new screen for my HP48SX I ahve used it so much. You I do have a newer TI but I still like reverse polish.

 I think I would rule that the staying spell would unravel when someone fired the bolt out of a crossbow or an arrow out of a bow. I do not think the intention of the spell was to provide longer ranges to missile, throwing weapons or to off set the weight of a suit or armor or equipment carried.
 I also think you have to remember when the spell was writen and what was the game inviroment then and how has it changed now. There is a huge difference IMO in spells now and what their creaters think of when writing them.

MDC

[Marc R]

The way the spell works, I don't think you could use it to get extra range (I re-read the spell and it changed my view per my last post above.) It's "Staying" it stops things from moving. . .it doesn't apply force, it applies resistance akin to moving up. For a 1# object, a "Staying I" effectively makes the direction you pick the same as straight up in terms of resistance. . .

So if you stand 100' north of an arbelest archer, and cast staying on the 1# bolt, picking north as the direction the object is "stayed" from moving, it would make shooting north at you exactly the same as shooting directly up. . .for a .15 arrow, it would be the equivalent of firing an arrow straight up against 6.67 G forces on a heavy world planet. . .which is a serious gravitational drag.

An Arrow would seem like a reasonable target. . .as an "F" spell it would allow an RR but I don't know that I'd use it just due to the annoyance of slowing play.

a 100# pull 6' stave longbow and a 500# pull 3' stave crossbow both fire projectiles at @ 120 f/s. The longbow accelerates the arrow for 2-3 feet, while the crossbow accelerates it for 0.5-1', so even though the crossbow has 5x the pull, the resulting speed is the same. . .the major difference, per above, is that the crossbow bolt should weigh 150-200% the arrow. (per RMC CL arrows and bolts both weigh 0.15, and there's no variation in short, long, light or heavy versions, <shrug>.)

Since it weighs more, it has more force and would take longer to slow down.

As to the spell itself "Staying I" is a fire-and-forget Force spell with a duration of 1 min/lv, not requiring concentration. . .I'd allow it to be used on an arrow. . .in fact, you could pick that arrow up and re-fire it from the bow a number of times in 1 min/lv, and I can't see any reason why shooting it would dispell the effect.

[Dax]

As to the spell itself "Staying I" is a fire-and-forget Force spell with a duration of 1 min/lv, not requiring concentration. . .I'd allow it to be used on an arrow. . .in fact, you could pick that arrow up and re-fire it from the bow a number of times in 1 min/lv, and I can't see any reason why shooting it would dispell the effect.

But reloading would be difficult, with a Staying spell preventing to move the arrow/bolt into one specific direction. 

[FatSteve]

RPN rocks!

That doesn't make me a nerd, does it?

Um... Maybe not, but it does put you on a waiting list...   

[RandalThor]

4.  I am able to maintain concentration on the incoming bolt for the needed duration. 

Really?!?

The question, in its final form, is of course,  "Is it safe?" 

Steve

Well, Steve-O ( ), I'm thinking........NO.

I don't think (unless you are a god or supernatural being or somesuch) you can keep concentration on a fired crossbow bolt. The speed at which it is travelling is too fast for your eye to follow, so once it is fired your spell is very likely trying to push on the crossbow now. Of course, at a hundred feet distance you may not even see the bolt in the crossbow in the first place.

Now, I see all that math and my brain just begins to revolt. It is MAGIC. I think the best way to adjucate this (and each GM can adjucate this to their hearts desire, of course) is the intention of the spell. From what that spell says, I do not think that that use is what it is intended for. Instead I would use something like, oh lets say, Deflection, or something like that. (Y'know, the spell that is intended to be used to deflect incoming missile weapons.)

[RandalThor]

Staying can be used for pushing the jar off the ledge to make a diversion or in their stronger forms making something too heavy to cross the ice so that it falls in. Stuff like that. Using one spell to do the job of another spell I think is a bad precedent.

[edxs]

I don't think (unless you are a god or supernatural being or somesuch) you can keep concentration on a fired crossbow bolt. The speed at which it is travelling is too fast for your eye to follow, so once it is fired your spell is very likely trying to push on the crossbow now.

Decent modern bows/crossbows have a velocity in the 300-350 fps range. It's possible to follow an arrow for its entire path of travel on a clean background, though it's very easy to lose it right out of the bow. A noisy background will make it hard, but not impossible. A 3xSD check could be done easily enough. Although I can say I'd rather wing it than do ballistic calculations while playing, if I were GMing I couldn't disallow this. It's a high-risk, high-reward use of the spell, and it's pretty creative (the first time).

Staying can be used for pushing the jar off the ledge to make a diversion or in their stronger forms making something too heavy to cross the ice so that it falls in. Stuff like that. Using one spell to do the job of another spell I think is a bad precedent.

Strictly judging the spell description these should both be impossible. The wording indicates it can't be used in induce motion, only resist it. It could be used to stop a jar from falling off the ledge, or stop the ice from opening up underfoot.

[RandalThor]

Strictly judging the spell description these should both be impossible. The wording indicates it can't be used in induce motion, only resist it. It could be used to stop a jar from falling off the ledge, or stop the ice from opening up underfoot.

Sounds good to me, though it really begs the question: "Why make that spell at all?" (Or: "Why is that spell so weak compared to others of its level?")

[markc]

 I have not had a lot of time to look at the spells but is there a difference between RM2, RMC and RMSS versions of the spell?

MDC

[Marc R]

In RMC "Staying I" prevents 1 object from moving in one direction with the force of 1 pound. It's a fire-n-forget F type spell, with a duration of min/lv. . .no need for concentration. . .but targeting a bolt, before it's fired, would provoke an RR vs the Archer, due to the "Inside the aura" rule on possessions.

It would seem to work in this instance, just the results are kind of snarky. . .it's not like the spell says "If cast on a missile weapon it results in -1 per foot of range." or anything like that. (It's effect would be far greater vs a 0.15 pound arrow than vs a 5 pound thrown melee weapon or vs a 50 pound thrown rock. . .so even a rule like that wouldn't really work).

I've never had it actually come up in play, steve's post was the first time I'd considered it.

[markc]

 I have had some talks with the GM who tuaght me RM2 back in the late 90's about just such effects from these type spells. Because I was looking into wareing armor that I did not have enough skill in to reduce the penalties. He sat down and told me his reasoning behind his decision which came out to a play balance issue and the line IMO it is beyond the idea the authors had for the spell or its effcets.
 IMO the list was to present a number of effects of limited power through D&D's 1st, Bigbys Hand type spells. And when you look at thoes spells the only effect they have is a attack effect.
 I can agree that I love magic to obay physics and all its laws but IMO you also have to be ready for all that it will encompuss and the future problems that may arise. Another reason a GM may have to say it will not work is that in the base list [like others have said] it targets mainly a static target and not a moving one. If a player wanted to spend the time to create a new spell list [not out of game time but in game time] then I may allow it with a few mods. Some of the mods may be moving target, weight of target, momentum of target [p=mv] and maybe some others as I sat down and created the new spell list. the mods may effect spell level, base PP's for spell or even additional PP for factors like HARP spells use.

MDC 

[markc]

 Another thing I just thought of is I might put a limit on the staying spells based on there ability to hold things back. Such as the weight it could effect if the target was moving slowly. Maybe 10% of the force the spell would be good but I need to see what the higher level spells might effect before I made a game decision.

MDC

[Dax]

And for the use of Staying against a person the GM might consider a Strength maneuver
to break free, i.e. the spell ends prematurely.

[markc]

And for the use of Staying against a person the GM might consider a Strength maneuver
to break free, i.e. the spell ends prematurely.

 I would deffinatly think of it that way.

 If you apply that reasoning to the bolt/arrow and range issue then IMO the bolt/arrow would break away from the spell effect and not be affected by it any more. But that is just me and my game.

MDC

[Dax]

Oh, yes.
And the short time, the spell works, results in a small penalty much lower than Deflection.

... The use of that spell (even if it is creativ) shouldn't be better than Deflection.

[FatSteve]

("Stop, let me figure the velocity conflict in this arrow before resolving the attack." might lead to your players beaning you with dice.)

Actually, it is my players who tend to whip out the HP calculators and go to town with the physics.  I'm just trying to be prepared.  Nobody actually tried the crossbow bolt thing.  I was just using that as an example to try to figure out the effect of Staying on objects in motion.  

Instead I would use something like, oh lets say, Deflection, or something like that. (Y'know, the spell that is intended to be used to deflect incoming missile weapons.)

What if you don't have that spell? Of course Deflections will work better.  But using something that doesn't work as well because that is all you have makes the game more interesting.  I encourage my players to find inovative uses for spells.

[markc]

What if you don't have that spell? Of course Deflections will work better.  But using something that doesn't work as well because that is all you have makes the game more interesting.  I encourage my players to find inovative uses for spells.
[/quote]

 You are doing what I try to do in my head before the game. I generally have 2 weeks or so to craft my game and sometimes I am ahead or sometimes I am behind so I have to do things on the fly.

 Since the spell was not designed for that but you want to give them an effect I might just rule that it subtracts off 1 or 2 from the targeting NPC's OB per rank they have in the list. IMO you should also limit the bonus to 10 or 20 as it should not come anywhere near the bonus of the spell that is designed to deflect[deflection] or stop[shield] arrows or bolts.
 I also tell them that I may rule this time this way but I may change my mind after further thoughts. Most like it but some do not as they like to take up game time presenting there case. I like to ahve them present there thoughts on the matter over email with what ever they have to suppost their idea. That way it is not it the heat of battle[GMing] and I and they can take their time and look at all the angles.

MDC

[Marc R]

Used against a person, or a bolt held by a person, it's an "F" they get a RR. . .and nothing pops an "F" spell with a duration except a dispel. . .merely strongly moving or resisting against a spell doesn't give you another RR or dispel the effect unless the spell actually says so.

1# of resistance to movement on a 200# person (with gear) would almost be unnoticable, it would be like walking into a breeze.

Deflections is cast on yourself, so it always works short of a spell failure, no RR.

Also, while 1# of contrary pressure is a lot of effect on an arrow or slingstone, it's not nearly so effective on a thrown axe or spear, and barely effective on a thrown 20# rock. Deflections are a flat penalty regardless of the size of the missile.

It's not an instant spell either, so you may need more time than you have to cast it on the arrow. If done in the same round, casting 75% goes off after missile fire 50%, unless you win the initiative. If playing with the 4 phase 25/50/75/100 round, it will always cast after fire.

So despite the lower level, it's considerably weaker than deflections.

My resistance to using it in play isn't based in effect or game balance, both of which seem reasonable, but in playability, due to the fact you'd need to calculate the result, rather than having a nice, easy to apply modifier listed in the spell description. Then again, I've never actually had someone try it, and the timing on it is pretty iffy, so it's not exactly a "good" move so much as a desperation thing.