If I were standing on top of a 5 story building that is inside a large rotating drum (space ship), and I stepped off the edge, what would happen? Would I fall?
Physics question
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Yes, but you'd shoot straight off into space while the building would continue to rotate. The building would either press into you while you fell, or move away from you depending on it's orientation to you relative to the direction of spin. The smaller the drum the more pronounced this effect will be and a thick atmosphere would dampen this effect.
Except for that 'shooting off into space' part, obviously.
Presuming this building is on the inside surface of the drum, of course.
I don't know if you ever did this experiment in science class as a kid, but there was one to demonstrate something like this. You had a ring that you rolled a marble around the interior edge, so that it spun around and around. Then a portion of the ring was pulled off, and when the marble reached it, it went off in a straight line.
Stepping off a building would be rather similar. You'd just need a second ring inside of the first one to represent the stepper's position on the top of the building. Once they step off, no longer being acted on by the rotation of the ship, they would fall at what would seem like an angle to an observer on the ground, if stepping off the face opposite the rotation, or would seem to be falling almost straight down, if they stepped of the rotation-ward side.
Except for that 'shooting off into space' part, obviously.
With the "shooting off into space" bit, I'm just talking about force tangent to the center of rotation.
Here is a video:
(Crash Course – Uniform Circular Motion)
https://www.youtube.com/watch?v=bpFK2VCRHUs
Gah. So much to unpack here.
Are you in zero G i.e. space? Air is filling the spaceship?
The key is what the building is doing relative to the spaceship. If you, the spaceship, and the building are all moving at the same velocity (presumably you are), and you "stepped off" (whatever that means in zero G), then you would float *very* slowly towards the edge of the spaceship.
I think you need to give us some more data points. In particular:
Is there gravity?
What is the relationship of the building and spaceship to the gravity?
What is the relationship of the building to the spaceship?
Are you in zero G i.e. space? Air is filling the spaceship?
The key is what the building is doing relative to the spaceship. If you, the spaceship, and the building are all moving at the same velocity (presumably you are), and you "stepped off" (whatever that means in zero G), then you would float *very* slowly towards the edge of the spaceship.
I think you need to give us some more data points. In particular:
Is there gravity?
What is the relationship of the building and spaceship to the gravity?
What is the relationship of the building to the spaceship?
I have a friend with doctorates in physics and astrophysics (and a bunch of other stuff - he seems to collect these things). This was his answer:
I see what you mean by the drum etc.
I don't think your friend understood your question. He's right about the ISS, but the ISS doesn't spin to create centripetal/fugal force, eh?
If you had a "drum" (with a building fixed to it) that rotated fast enough to create 1G of force, then you would fall off the edge. Not straight down, mind you. You would fall in a curve relative to the ground.
The ISS is in a state of zero-G because the gravitational pull of Earth is balanced by the centripetal force of the station's orbit, so yeah, no net force on the ISS.
I don't think your friend understood your question. He's right about the ISS, but the ISS doesn't spin to create centripetal/fugal force, eh?
If you had a "drum" (with a building fixed to it) that rotated fast enough to create 1G of force, then you would fall off the edge. Not straight down, mind you. You would fall in a curve relative to the ground.
The ISS is in a state of zero-G because the gravitational pull of Earth is balanced by the centripetal force of the station's orbit, so yeah, no net force on the ISS.
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Haven't put pencil to paper on this one, but I believe that when you step off the building, you will continue in a straight line at the local velocity of the building at the moment you take leave of it, in free fall. The building and the inner surface of the drum, however, will continue in uniform circular motion at the angular velocity of the drum. This means that building and inner edge of drum will accelerate towards the drum axis of rotation while you move at constant velocity. As viewed by a horrified observer on the building roof, you will appear to accelerate towards the drum inner edge uniformly: She will see you fall.
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Argh, argh, no, don't make me re-visit rotating reference fields...
Okay, I don't have to. Wikipedia's entry on the Coriolis effect has a nice animation that shows it; you're the black ball. You would "fall" off the building, but you would appear to swoop off to one side as you fell. Depending on where the building is located, you might seem to zoom away from it, or zoom sideways parallel (or at an angle to) its wall, or you might get pressed into the wall, which might give you enough friction to save your life (depending on how fast you fall on that space station).
Okay, I don't have to. Wikipedia's entry on the Coriolis effect has a nice animation that shows it; you're the black ball. You would "fall" off the building, but you would appear to swoop off to one side as you fell. Depending on where the building is located, you might seem to zoom away from it, or zoom sideways parallel (or at an angle to) its wall, or you might get pressed into the wall, which might give you enough friction to save your life (depending on how fast you fall on that space station).
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I did intend to think about how Coriolis complicates the picture, but it makes my head spin.
Oh, yeah. Dickson has nailed the description much more eloquently.
The key is that you continue at a constant velocity tangential to that of the rotating station -> i.e. towards the ground, eh.
Coriolis does complicate matters, but I think that would depend on the size of your rotating station/ship, indianroads. In a small station, the consequences of the Coriolis effect probably wouldn't be noticeable. In a very large station/ship (like KSR's Aurora), it would be noticeable.
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Gravity generated inside a rotating drum or ring will be less as you approach its center (or reduce the radius). There are calculations you can find on the web about the amount of gravity generated based on the radius of the drum and the speed at which it rotates.
a=ω2r
a=acceleration of the fake "gravity" called centrifugal force.
ω is the angular velocity of the ring or space station
r is the radius of the ring
This is a handy site that allows writers to plug in desired numbers and determine the radius and and angular velocity for the spinning ring or drum on a space ship to generate a particular amount of "gravity." It also indicates when the values would result in considerable discomfort (such as motion sickness) to its occupants.
https://www.artificial-gravity.com/sw/SpinCalc/
One thing that is almost never mentioned in books that take place in outer space with gravity generated within a ring or drum in a ship or space station is that, unless the radius is very large, you'd get a noticeable Coriolis effect. Objects would appear to deflect sideways antispinward as they fall to the floor. The distance which the object (or in this case, your falling person) would deflect would be based on the tangential velocity. The speed at which they fell would depend on the centrifugal force, which would increase as they grew closer to the "ground."
a=ω2r
a=acceleration of the fake "gravity" called centrifugal force.
ω is the angular velocity of the ring or space station
r is the radius of the ring
This is a handy site that allows writers to plug in desired numbers and determine the radius and and angular velocity for the spinning ring or drum on a space ship to generate a particular amount of "gravity." It also indicates when the values would result in considerable discomfort (such as motion sickness) to its occupants.
https://www.artificial-gravity.com/sw/SpinCalc/
One thing that is almost never mentioned in books that take place in outer space with gravity generated within a ring or drum in a ship or space station is that, unless the radius is very large, you'd get a noticeable Coriolis effect. Objects would appear to deflect sideways antispinward as they fall to the floor. The distance which the object (or in this case, your falling person) would deflect would be based on the tangential velocity. The speed at which they fell would depend on the centrifugal force, which would increase as they grew closer to the "ground."