Buoyancy, is it really just reverse gravity?

I was experimenting with llSetBuoyancy this morning, and noticed what might have been some odd behavior. Unfortunately I didn't save any of the data I generated, so maybe I'm wrong.

Objects set to > 1 buoyancy seemed to accelerate over time. Are the really just "falling upwards" at a graviational constant I set with llSetBuoyancy?

Granted, my understanding of -real world- physics ends with one general credit course in college. Perhaps I'm misunderstanding 1st life's equivalency to Buoyancy.

In the real world, buoyancy produces an upward force in an analogous manner to gravity providing a downward force. So, yes, a buoyancy >1 in SL should produce an upward acceleration. No surprises there.

And, I've taken considerably more than one university-level physics course, so you can believe what I say in this regard.

Thanks for the info. I couldn't understand why my >1 buoyant objects continually accelerated upward. I had assumed otherwise.

Quick related question, do items in SL have air friction to cap the maximum drop/rise speed through the atomsphere?

can you help me with my hw? I suck at Physics

I haven't done any systematic investigation, but anecdotal evidence suggests there is some air resistance affecting object dynamics. Determining terminal velocity and drag coefficients is left as an exercise to the reader.

I asked Cory Linden about this. The physics engine simply cuts down the speed of something to about 50m/s whenever it notices an object moving faster than that. So an object having a force continually applied moves faster than 50m/s, because it manages to accelerate between being cut back to 50m/s. Something like that.

Anyway, when falling you are under a continual acceleration of -9.8m/s^2, so you move at around 52m/s. If you are moving forwards at over 50m/s you get cut back to 50, then as you start falling you get more downwards velocity. As your downwards velocity increases, it puts your speed (magnitude of velocity) over 50, and you get cut back again, but this time your direction is more downwards than it was before. Repeat over a few seconds, and you lose much of your forwards velocty, as you are now falling almost vertically downwards, at 50m/s.

Hope this helps.

My experiments seem to show that there IS air resistance.

As Seifert said, terminal velocity for an uladen Human is roughly 52 meters/sec. (African OR European)

Maximum velocity, without hacks, is 250M/s.

And Morgan: Yes, bouyancy is another form of acceleration. In the real world, bouyancy is reduced as air pressure goes down, so you eventually reach a balancing point where your lift from bouyancy equals the downward acceleration from gravity. But in SL, I believe bouyancy is infinite: you can keep going up and up forever.