MtA 2e, Operation: Railgun
How fast could a group of mages make a chunk of steel move?
Spells not being used
First, let's start with the spells we won't be using.
Death 3, Quicken Corpse, page 131
This would be an excellent start to the calculations, but we're currently interested in firing a chunk of metal, not a zombie.
Forces 3, Gravitic Supremacy, page 144
This spell only affects jumping distance.
Time 2, Tipping the Hourglass, page 188
If we wanted to accelerate a living being to this speed, this spell would allow them to actually be able to control their movement, but we don't need that here.
Spells being used
Forces 1, Kinetic Efficiency, page 141
Adds the caster's Force dots to the target's running Speed.
Forces 3, Telekinesis, page 144
Adds the spell's Potency to the target's Speed.
Forces 3, Velocity Control, page 145
Double's the target's Speed per level of the spell's Potency.
Forces 4, Levitation, page 145
This spell lets us take the object to the air and also sets the initial air speed to the spell's Potency.
Space 1, Ground-Eater, page 173
Adds the spell's Potency to the target's Speed.
Time 3, Acceleration, page 188
Multiply the target's Speed by the spell's Potency.
The mages
As the scenario is already unrealistic, even for a super-high fantasy TTRPG, we'll keep adding to it. This scenario will have a Gnosis 3, <required Arcanum> 4 mage casting each spell. They can make use of any number of appropriate Yantas in order to cast the spell, can ritual cast, can touch the object, and they'll each only be require to get a single die to roll, which we will assume succeeds due to a Fate mage backing all the spellcasting.
The target
The object being fired is a chunk of steel, speed 0.
The math
| Action | Speed bonus | Running total |
|---|---|---|
| Starting | 0 | 0 |
| Levitate | +11 | 11 |
| Kinetic Efficiency | +11 | 22 |
| Telekinesis | +11 | 33 |
| Ground-Eater | +11 | 44 |
| Acceleration | x11 | 484 |
| Velocity Control | x211 | 991,232 |
Total: 991,232
What that means
The book gives us a scale for speed of common beings:
| Factor | Species |
|---|---|
| 1 | Turtle |
| 3 | Human toddler |
| 5 | Human adult |
| 8 | Wolf |
| 10 | Caribou |
| 12 | Horse |
| 15 | Cheetah |
If we assume that a Cheetah's top speed is 120 km/h and that this table scales linearly (though it doesn't), then the speed of our projectile would be about 7,929,856 km/h, which is 2,202,738 m/s, which is 0.7% the speed of light and Mach 6,479.