How quickly do things fall?

[quindraco]

How quickly do things fall? I think page 400 implies that everything has a terminal velocity of 500 feet (A character can’t cast a spell or activate an item while free-falling unless the fall is greater than 500 feet or the spell or item can be used as a reaction.), regardless of atmosphere thickness (including water) or gravity, but I can't find anything concrete on the matter. The description of Gas Giants on page 294 implies that there is some maximum falling speed which is less than light speed and depends on gravity.

[Jasque]

Dotting for interest. I had this question as well, and I could not find any answers.

[Pantshandshake]

Well, on earth, a person would fall around 570 feet in 6 seconds, so that terminal velocity bit you mentioned seems like you spend your turn falling, and if you still have fall left, you get a new turn mid-air.

If you want to figure out how fast a person would fall on another planet, you could either:
a; figure out gravity, atmospheric density, and 'oddities' (sudden thermal updraft!)
b; handwave most of that and just say 'more than 1g, fall 2x, less than 1g, fall .5x.'

[LynchedDM]

I was going to dig up a big explanation that I have saved from years ago (back when 3rd edition D&D was still the "IT" thing), but then I found this:

https://www.omnicalculator.com/physics/free-fall

It doesn't account for atmospheric density, but it is still pretty handy.

[Fuzzypaws]

There are all kinds of factors which would affect this like whether you are spread out or balled up, temperature and thus density of the air, etc. But in general, it's simpler to just use round approximate numbers. On Earth in real life, a human in freefall would fall about 500 feet in the first round (6 seconds) at which point they would reach terminal velocity, and fall 1000 feet per round thereafter. So they'd fall a total of 1500 feet after 2 rounds, 2500 feet after 3 rounds, etc.

[kaid]

This is where your GM earns his money. How fast you fall would depend on what the local gravity is and potentially atmospheric density.

If the atmosphere is really dense the time it takes you to hit terminal velocity would go up simply due to friction.

Conversely if you are on an airless planet with 1g gravity you are going to hit terminal velocity pretty fast because wind resistance/air density are nil.

Take sky diving on earth if you are spread out in skydiving mode your max speed is around 54 meters/s but if you pull your arms in and stay tight its closer to 90 meters/s

Now take the example of the guy who jumped from the edge of the atmosphere who hit 830 mph; 370 m/s. That is how massive a difference air density plays into this.

So unless your GM wants to math the hell out of it some rough estimates are probably the best call and just play it by ear.

[kaid]

Actually slight correction to the above. On an airless planet you would accelerate at the speed of gravity until you impact the surface or otherwise do something to prevent this sudden stop. So in a 1 g airless situation you should accelerate at 32 feet per second until impact. So in an airless environment I don't think there technically is a terminal velocity it just depends how long you are accelerating under the 1g effect until acted upon by some other force or impact with the surface.

If this is coming up in a group probably best to just get a rough estimate for earth normal air pressure/density and then add some gross adjustments if you are on other worlds for light density/heavy density/no atmosphere and differing gravity conditions.