Rego magic movement speed

There's a certain tension in the game between "things in the Middle Ages as we imagine contemporaries understood them" and "things in the Middle Ages as we today believe they really were". When it comes to physics, I'd rather stick to the "as they really were" interpretation.

Medieval scholars via Boethius (see en.wikipedia.org/wiki/Boethius#De_arithmetica ) always had access to Euclid's use of proportions, and medieval merchants applied the rule of three.
But dividing distance by time was generally considered an impossible or wrong operation - so mph or km/h was not even a measure. Of course they did compare different means of moving by comparing the times needed to move a given distance, and thereby decided which was faster.

Evaluating the experiment conveyed to us by Viviani, Galilei (see en.wikipedia.org/wiki/Galileo_Galilei#Physics ) would not need to address quantitative speed or acceleration, but just to compare falling times. So he could use widely accepted academic terminology and methods, and tackle the problem in Aristotelian mechanics directly.

Of course ArM5 is not about players mentally jumping through hoops when designing spells. So modern speeds to be achieved with spell guidelines are given in mph. But extrapolating modern, quantitative speeds or - more logically - accelerations to generate further guidelines would look really out of place to me.

Cheers

That is the reason, in my games we used the scale I proposed of walking man/running man/running horse/flying bird of prey. Every magus can relate to that and when designing a spell can say "as fast as...".

However it does not address the issue that depending on the form, there is a wide discrepancy. For corpus, you cannot go fast, except if you resort to teleportation. But may be there is a logic, Corpus being specific to human body, you cannot go faster than a running man, an intrinsic limit of the Form.
That's why Auram would allow to go faster, every mages have witness the speed of the wind. If we assume that there is a similar intrinsic limit in Auram form, the cap would be around 100-140 km/h (~60-85mph) altough it could go higher. Although travelling at hurricane speed would require some form of protection. Obviously, in this case the wind is carrying the target, and the accuracy is more tricky.

But if I follow the same logic with Terram, I hit a snag. Normal speed for natural earth phenomena is glacially slow. Here we are talking about centimeter per year at best. However, all throwing spells (Vilano's sling and its variants) show that it is possible to go much faster. Obviously, catapults and slings prove that it is possible for stone to travel lethally fast. It simply requires a intermediate Tools. But it this case, why can it not been extrapolated to Corpus ? Obviously if the spell has momentary duration, it means that you are flinging the target, which is a good way to get rid of opponents, not so much to travel. But a Concentration duration should allow the caster to travel at relatively high speed.

Speed of a slinged stone is about 30 m/s or close to 110 km/h, so taking the base guideline for Vilano's sling (I do not have my books with me) allows such speed. +1 for Duration of Concentration. There is no need for size increase since the base size is about 1 cubic meter of dirt....
But I do not think it matches Corpus guidelines...

I would say Auram is faster if a magus is light enough to be blown easily by the wind. Otherwise you would need hurricane force winds to move a normal human around. A simple MuCo to lighten a human would make it work.

I like the approach of "Speed of [Form]" and particularly the idea of a spell that allows you to move as fast as you can, presumably for a lowered fatigue cost for a duration, but there are problems here.

The intrinsic speed of Terram is very slow. The speed of a mundanely slung stone is not based on Terram, it's the result of a mechanical amplification of Corpus; an arrow is normally propelled at a speed determined by the strength of the bow, which is generally Herbam.

... which is a problem, as we're getting increasingly abstract. Stones and arrows don't have a natural speed. They move due to force imparted to them, and there's no Form for impetus, so far as I'm aware.

You could simply back calculate the speed, based on damage. A spell of X level does Y damage, and therefore the [object] is moving at Z speed. That works for weapons, but not particularly well for larger body travel.

You might also look at the ReAn effect on the horse in RoP:M (my books are packed for moving, so I can't be more helpful with a location or name). There a specific distance and time are provided and the base is listed.

So that's my point. Why would Rego be based on the speed of the Form itself? I mean, I do understand that the stronger the spell, the faster you can move something, that's fine. And I'd agree that certain Forms should require less effort to achieve higher speeds. But Rego isn't the Art that "controls and changes things naturally as they would do by themselves". Is the Art that "controls and changes things in any way that it's naturally possible".

You can teleport with Rego because it's naturally possible for something to "be" in a different place than it is even if it was unable to relocate itself (or, even if there's no way to naturally relocate something into a particular place, what matters is that it's still a place where that thing could "be"). You can use Rego to lift an object, because things can usually be lifted, even if they can't lift themselves (and while things can't be held against gravity unsupported naturally, well, that's what the spell does through its duration. They will naturally fall when it ends). You can use Rego to craft a sword from a slab of Iron because it's naturally possible for iron to be forged into a sword, even if it isn't able to forge itself.

So, why wouldn't Rego be able to move something at any speed that it could possibly "be moved", and not just "move itself"? You shouldn't need Animal to move something as fast as a horse, nor Auram to move it as fast as the wind, and neither should those Forms be limited to those speeds, unless you were specifically creating a horse or using wind to move things. Otherwise, I'd consider that you'd need Corpus to forge a sword, to account for the fact that is a person what usually forges swords, and also Ignem (possibly Aquam) to account for elements involved in the crafting process. But you don't. That's even specified.

I'm not really arguing what method should we use to measure speed, honestly. Just the fact that there's a limit. At least, a limit as low as what seems to be implied. I'd consider valid if you told me that you can't move something as fast as lightning without actually turning into lightning or just teleporting, because that's something kinda unfathomable even to modern people, but I don't think it'd be hard for anybody to picture somebody flying (or at least being hurled) as fast as if flung by a trebuchet. Hell, some people might even have seen that for real, lol.

I do not know of any hard limits on magical speed. It may be something implied that I am unaware of, but from the sound of things it seems like something I would ignore anyways. But my thinking is thus. If Rego level "x" moves a thing at speed "y", then level x+whatever would move that same thing a proportional amount faster.