artificial gravity

[katerinah1947]

They will, if they begin with no motion relative to each other, other than directly toward or directly away from each other. Here's a place to play with the idea:
https://phet.colorado.edu/sims/my-solar-system/my-solar-system_en.html

Set the slider to "accurate" and unclick "trace" to get a good look at it.

Hi,

I am on an iPad. Adobe8 is needed, and it won't download. I will try harder later. I also teach, but in mentor mode only and meant by me as a one on one type of interaction, gravity at times. So, visually, gravity is a simulation that plays like a video in my heart and looked at with my minds eye, before or during my mentor interactions. Sometimes it is only thought or thought images.

Thanks anyway. For others not you, Gravity is force at a distance and more, but I don't know those 'mores' yet like making space because only mass makes space and only mass makes gravity also.

Again, for others not you, the result when measuring and confirming the results of others, gravity, decreases faster, than the amount of distance separating the objects. It does that by a lot. I don't want to use a foreign language yet.

Whether any person here uses a gently tilted ramp with a rolling ball, or a strobe and a camera with a ball and a ruler, gravity can be measured on earth, which is the lesson.

The lesson is to see for yourself. By seeing, one knows that Nut jobs, known normally as professors teachers researchers, are actually uncomfortably correct.

Those planets even with some motion, again not for you, are affected still by each other. If they have beginning motion away, and if it is enough as gravity falls off quickly, (relative distance times relative distance, and not, relative distance alone, thus resulting in 4 changing the force by 16, not 4, and 1/4 changing the force by 1/16, not 1/4th.), although the planets will still never collide then, the speed at which they would be traveling is changed to a new speed because of that other planet.

In my head video, All of your statements are run, and they are the way you said.

Off topic, it is in running head videos, or pictures, when I can see atoms in a junction that way, with all the components needed for the question at hand, that I have used and still do, for solving some but not all problems.

Now it seems, computers and even MathLab do that.

LOVE,

 

[The Barbarian]

Centrifugal force a fiction?

 

[SkyWriting]

Is the "Hollywood" portrayal of a space station even real?

By definition, no.

For that, go to the videos

Tour the International Space Station - Inside ISS - HD

 

[SkyWriting]

Once one has "jumped" that contact is broken. How would it be re-established?

The trajectory across the middle would look to the observer as a straight line, and to the "spinner" as a curve.
But the effect would re-establish at contact with the other side as the spin tries to change the natural
course of the object. Changing the natural course of the object results in a "new gravity" or force.

 

[essentialsaltes]

Centrifugal force a fiction?

Well, as Goldfinger(?) correctly notes, the term appears due to the choice of a non-inertial coordinate system.

 

[The Barbarian]

Yep. BTW, my prediction that a person jumping up in a rotating space station, would not notice a difference from gravity, is true, only if the station has a very large circumference. You would come down in the same spot, but if the curvature was significant, you'd come down at a noticably different angle than you went up. You'd still fall, but there would be this weird "force" tipping you over. Fictional, I suppose. If the station's RPM was low, relative to the linear speed of the station, you wouldn't notice. I suppose that's the case for someone jumping up on the surface of the Earth.

 

[whois]

Yep. BTW, my prediction that a person jumping up in a rotating space station, would not notice a difference from gravity, is true, only if the station has a very large circumference. You would come down in the same spot, but if the curvature was significant, you'd come down at a noticably different angle than you went up. You'd still fall, but there would be this weird "force" tipping you over. Fictional, I suppose. If the station's RPM was low, relative to the linear speed of the station, you wouldn't notice. I suppose that's the case for someone jumping up on the surface of the Earth.

i disagree.
you will not "fall" on the station, it's impossible because there is no gravity.
instead you will be "thrown" in the direction of rotation.
this implies that you would experience a kind of stumbling effect upon landing, sort of like someone pushing you.

other strange effects would occur when you stand still and turn around 360 degrees, or when walking and make a 90 degree turn.
these effects have to do with how gyroscopes react under applied force.
for example, tipping the rim will cause the axis to precess in a plane 90 degrees from the applied force.
using a compass model, this would be like applying a downward force on the eastern edge of the rim will cause the axis to precess either north or south.

here is a scenario of a different type:
what if your destination was exactly on the opposite side of the rim?
which direction would you go, in the direction of rotation or against it?
it seems to me that going with the rotation would allow you to get there quicker.

 

[The Barbarian]

You'd fall in the same sense that you fall on Earth. As you jumped up, your inertia would take you in the same tangental path you were on at the time you jumped. The floor would move, too, but being curved, would be accelerated toward you, as if you were falling. But you'd feel an odd "force" tipping you as you fell, unless the radius was very large.

Interestingly, if you ran in the direction of the spinning, you'd find that it made you heavier, and if you ran in the opposite direction it would make you lighter.

 

[whois]

You'd fall in the same sense that you fall on Earth. As you jumped up, your inertia would take you in the same tangental path you were on at the time you jumped. The floor would move, too, but being curved, would be accelerated toward you, as if you were falling.

this all seems correct except for the "falling" part.
any time you are "disconnected" from the station you are weightless.
jumping up for example, as soon as you leave the floor, the motion of your body will be the vector sum of your upward momentum and the rotational speed.
there is nothing attracting you.
you will continue in the summed motions above until intercepted by one of the walls of the station.
this is different on earth.
gravity will retard your summed motions until you are attracted back to it.
the only exception being if you managed escape velocity.
in this regard, "escape velocity" on the station would be very low

But you'd feel an odd "force" tipping you as you fell, unless the radius was very large.

yes, and it's these "odd forces" i wish to explore in this thread.
descending from the axis to the rim, lifting heavy objects over your head, certain body movements, and the movement of other objects.
pouring water from a pitcher or a geyser type water fountain, both of these will exhibit motions that seem to be a "wind" blowing in the opposite direction of rotation although there is no wind.

Interestingly, if you ran in the direction of the spinning, you'd find that it made you heavier, and if you ran in the opposite direction it would make you lighter.

yes, i mentioned this earlier in the thread.
it seems like if you ran against rotation and jumped up at the right time, you could achieve "escape velocity" and be stuck in mid air.

i believe life on a ferris wheel type of station would be very interesting.

 

[The Barbarian]

it seems like if you ran against rotation and jumped up at the right time, you could achieve "escape velocity" and be stuck in mid air.

If you could get the net forces on all sides to zero, yes. But then you'd have the illusion of flying rapidly over the floor. And air resistance would eventually pull you back down.

 

[whois]

If you could get the net forces on all sides to zero, yes. But then you'd have the illusion of flying rapidly over the floor. And air resistance would eventually pull you back down.

ah yes, i forgot about air resistence.
the question here is, how much would this affect you?
there might not be as much as you think.
but yes, it seems it would eventually drag you back down.
but how can it with no gravity?
the laws of physics says even a little air resistance must bring you down, but i don't see how.

 

[The Barbarian]

Because it's pushing on you, you will start to move with the motion of the floor. It's turning, so it will change direction. But your inertia will move you sideways and toward the floor, which will be turning upward before you.

 

[whois]

Because it's pushing on you, you will start to move with the motion of the floor. It's turning, so it will change direction. But your inertia will move you sideways and toward the floor, which will be turning upward before you.

okay, but this isn't technically air resistance.
it's actually a "wind" type of phenomena.
again, this isn't any type of gravity, you are being pushed along in a straight line until you intercept one of the walls of the station.

 

[Davian]

Space station artificial gravity is tested in a centrifuge of the type seen in "2001: A Space Odyssey" at NASA Langley Research Center. Two different rotation rates simulate one-tenth gravity (0.1 G, station rotating at about 4 rpm) and one-half gravity (0.5 G, station rotating at about 9 rpm).

 

[Davian]

okay, but this isn't technically air resistance.
it's actually a "wind" type of phenomena.

I would use the term 'boundary layer' to describe the layer of air that 'clings' the surface of a moving object (the rotating 'floor' in this case).

The boundary layer of air is what accelerates you (dependant on your proximity to the floor), causing you to 'fall' to the 'floor'.

 

[whois]

I would use the term 'boundary layer' to describe the layer of air that 'clings' the surface of a moving object (the rotating 'floor' in this case).

The boundary layer of air is what accelerates you (dependant on your proximity to the floor), causing you to 'fall' to the 'floor'.

yes, that seems correct.
plus, after a certain length of time, the entire air volume would attain a slow speed in the direction of rotation.
this brings up something else too.
the ring will no doubt be pressurized
i'm not sure if this would have any effects though.

 

[The Barbarian]

okay, but this isn't technically air resistance.
it's actually a "wind" type of phenomena.

Since motion has no meaning until you pick a reference point, it's the same thing. There are no privileged points of reference.

again, this isn't any type of gravity, you are being pushed along in a straight line until you intercept one of the walls of the station.

Yep.

 

[SkyWriting]

You jump up vertically, and will LAND upon the same spot ??
iow: you will NOT lose the velocity you SHARE with the train
while you are in the air

Inside the train, you would land where your feet left.
Outside the train, the wind would blow you backwards.

 

[SkyWriting]

To take the bucket example (and stretching the analogy) although the water will stay in the bucket, that's because there is a constant outward force acting on it. If a diver were standing on the bottom of the bucket, and jumped upwards, that jump would negate that force, and I don't see how the force could be reapplied afterwards? Gravity is constant, but centripetal force only affects objects at in contact with the spinning inner surface. Once one has "jumped" that contact is broken. How would it be re-established?

If the (red shorts) tosses a ball inward, you would see it fly in
a straight line to where it would connect with the wall again at (red shirt) and the wall would attempt to change the balls direction there.
It will feel heavy as long as the wall keeps changing the balls direction.

I have experienced the effect. In the carnival ride where the floor drops away in a spinning bucket
pushing your hand from the wall, the feeling of gravity lessens on your hand. Your hand feels very heavy
at the wall but at an arms length further in, it feels maybe 50% less heavy.

 

[Paul of Eugene OR]

No, but in your example, you are pulled back to the train's floor by the Earth's gravity, not the trains momentum. In a centripetal space station, you'd maintain your angular momentum, but you wouldn't be pulled back to the floor.

But the floor, going in an arc, would move up to impact YOU. If you are focused on the floor as being stationary, it will seem as if you fell to the floor.