Levitate ws Physics, I feel a headache coming on... Options

[Lagomorph]

So the thread on invis+silence brought up a point for me that I thought would be best spun off into a different thread.

Does levitate just break the laws of physics (conservation of mass/energy) or is there a way to get it to make them work together?

Here's a question for you to illustrate the point:
A 100kg mage is in a 100kg cage on a scale, when the mage is at rest the scale shows 200kg, when he levitates does the scale read 100kg or 200kg?

[JBlades]

The scale would read 100kg, as the levitate spell is the application of energy to cause lift, hence while the mage still weighs 100kg, he no longer exerts that force on the scale, it has become potential energy because he's been lifted exactly as if a troll came along and picked the little guy up. No violation of physics has occurred.

[pbangarth]

Let levitate work within and against the magnetic/gravitational field of the Earth and there is no problem. the scale would measure 100 kg. because the weight of the mage is pressing against the gravitational field directly, via the effects of the magic spell.

As a similar example, say you had a plastic (or any other non-magnetic substance) balance on one side of which was a magnet, countered by an equal weight on the other side. Now, bring an opposite pole magnet underneath the balance arm and magnet on the first side.

The magnet in the balance would lift, and the scale would no longer feel it at the same weight it did to begin with.

[Buster]

[Hank]

If levitate lets you float across pressure plates, that scale had best read 100kg.

[Gelare]

Forgive me, but I can't help but point out...it's magic. :D
But if you're looking for a challenge as far as ways to reconcile magic with physics, everyone always loved those threads about the Movement power. Conservation laws? Bah! Bah, I say!

[Ol' Scratch]

It just breaks the laws of physics. Just like Fireball creates a huge ball of flame out of thin air that goes hurtling wherever you wish, Shapechange temporarily destroys or creates matter out of thin air, and Turn to Goo does... whatever it does out of thin air.

Magic follows its own rules and only interacts with our world and our universal rules on a secondary level.

[Lagomorph]

[kzt]

Ok, you levitate into an elevator. Elevator zooms up at 10 meters per second (it's a FAST elevator). This (we'll say) exceeds the max speed of the levitate spell of 6 meters per second. Does the levitate guy bounce off the floor, or is he fine because the elevator isn't moving relative to him?

[Paradigm]

KZT, that's a brilliant question. One I'd be inclined to rule over against the players and say that it'd likely catch up to them. After all, they could've always taken the stairs rather than the deathtrap on a wire.

I suppose that magic fudges the rules enough to support either ruling, but it'd be a nice example of incompatability of tech and magic in my eyes.

[GryMor]

Like most magical effects, Levitate, as written, presumes a preferred frame of reference. Normally the preferred frame of reference is the Earth's surface on a large scale, possibly even the astral shadow of the Earth.

The question then arises as to when an alternate frame of reference can be substituted for the Earth, and how transitions between these frames of reference occur. There is, additionally, the special case of when Levitate initiates while the subject is traveling at a velocity in excess of that which levitate can sustain with respect to it's current frame of reference.

Observations:
1. The frame of reference of a levitate spell need not be (and usually won't be) an inertial frame of reference. Specifically, the Earth's surface is under a 1g acceleration.
2. It is probably for the best that levitate not provide a corrective impulse to assert it's velocity restraints, otherwise, at weak force, it becomes an absurdly effective means of converting drivers into chunky salsa.
3. Levitate probably SHOULD assert it's velocity restraints in some manner, otherwise it isn't particularly useful as a parachute and opens up the door for very long range heavy projectiles (accelerate car towards target, levitate 600kg lance braced on the car, stop car allowing lance to continue onwards).
4. If there are frames of reference besides the Earth (a airliner in flight or ship in high seas for instance), it should be possible to acquire the Earth's frame of reference by means of getting far enough away from the alternate frame of reference's associated body.

Other note:
With regards to where you put the scale to include the 'weight' of the levitating mage, the question makes as much sense as asking where you would put a scale to measure the weight of the earth. The answer is, that the weight of the Earth mage system is not a well defined concept, the system is in free fall around the sun, and thus, from a certain perspective, has a weight of 0.

[Kyoto Kid]

...I've learned trying to rationalise magic with physics is a quick ticket to either a cerebral hemorrhage or drinking a half bottle of cheap whiskey to forget why you tried to do so. I've banged my head against the wall too many times on this topic (the whiskey at least helps to dull the pain) :grinbig:

I'll let someone else say it for me...

[Mercer]

[GryMor]

There is precedent for using the containing objects aura as the frame of reference. Wards work this way (allowing for warded vehicles but not uncontained mobile ward bombs of magey destruction/

[DTFarstar]

I generally go with the intent of the caster. If you want it to move with the object it does, if you don't it doesn't. Generally they could get either effect if they thought about it anyway, and dumbing things down a little bit speeds up gameplay a lot.

Chris

[Critias]

[JBlades]

[Fortune]