What happens?

Interesting to think that the change in gravity would crush you in free fall.

But I think it would just be disorienting without hurting you.

Would like to know how many times you would have to go in and out of the portal at that speed until airdrag has slowed you to a stop.

My guess is that you go back to >>>/plebbit/

>>9052172
>> earth's gravity will instantly crush
No. Fuck no. Why the fuck would you think that would happen? The person doesn't go through the portal instantly, they go through at terminal velocity.

Now if you could magically switch earth's gravity instantly, it wouldn't crush them because everything falls at the same rate. If you had a magical way to generate repulsive gravitational forces you could, in a vacuum, instantly go from zero to many kilometers per second. Because everything moves at the same rate one would not be crushed.

>>9052172
Portals are not real.
Portals are not science
>>>/v/
>>>/reddit/

>>9052172
Why would it crush you? The new direction of gravitational pull will start slowing you down.

It's literally throwing a ball upside and seeing gravity grind it's speed to a halt and then reversing it.

Or am I missing something?

>>9052172
the maximum acceleration any particle in the body would experience is 2g, fighter pilots can withstand 9g, so it wouldn't be the gravity that crushes bones and organs, though if they hit something they would likely break something

>>9052271
The ball scenario is different, because you have no change in acceleration. This case is more similar to standing on a platform which is the taken out from under your feet. The magnitude would be double this, but no damage would occur, since there is barely any discomfort at such low levels. You might get a bit sick though.

>>9052172
On left, gravity force of m*g downwards and air resistance balancing that upwards.
On right, gravity force of m*g downwards and air resistance approximately equal to that on the left but in opposite direction.
So you would feel suddenly accelerating downwards. Not being crushed.

I have completely ignored conservation of momentum here because it's a portal problem and there is some serious fuckery with momentum.
If you think that instantaneous change of momentum which is the result of an infinite force then I can understand why you think the person would be crushed.
But that is to silly. If you are willing to accept that this portal is able to move something instantly through space with no issues, then why can it not also change the direction of the momentum?

>>9052172
I've seen a lot of retarded threads about portal physics, but congrats. This is the most retarded one by far.

>>9052172
We'll go by standard terms
1 G = force of gravity on earth

(1 G) - (-1 G) = 2G

So a person in free fall where gravity was switched would experience 2 gs of force at some given time.

The human body can handle 2gs of force for short periods of time, even long periods.

>>9052172
You are correct. Just like how everyone who has ever bungee jumped has been crushed on the return.

>>9052172

Depends.

The portal needs to be deep enough to completely cover the person. Your first molecule must not exit the portal before your last molecule is inside it. Otherwise you will collide with yourself with double termial velocity.

>>9052408
This is unbelievably stupid. The amount of force on the object never exceeds 1g. What happens is the force changes instantly from 1g to -1g (from its reference frame). What happens in this situation is jerk (a') approaches infinity.
If you are talking about the stresses in terms of compression, then you only calculate in terms of the forces that are acting through a plane in one direction, which is only 1g of force (this can be performed because the body will be in dynamic equilibrium when experiencing the forces of both side).

>>9052338
You have somehow managed to correctly describe the direction of the forces, but then get the conclusion completely wrong.
On both sides of the portal, gravity acts towards the portal. This results in compression.

>>9052366
Too many people in this thread don't even understand basic dynamics.

>>9052534
not him but as a particle passes through the portal it will be pushed at one end by particles that haven't passed though and pulled on the other by the new direction of gravity, excluding other physical pressures like that exerted by the heartbeat its acceleration will be about 2g tops

>>9052172
>Acceleration at 1 g would kill you
No

>>9052271
The difference is that the change in the movement direction compared to the gravity happens when speed is 0 on a ball and happens at max speed with a person.
Either way it wouldn't kill you, you'd just experience a deacceleration of 2g, but since gravity acceleration affects ALL the mass in your body, and not just the surface of contact(like on a jet) you wouldn't even feel pain or pressure in your body because of acceleration, just highly desoriented.

>>9052544
I have studied dynamics as a part of my degree. Net acceleration will be 0, as the force acting on both sides of the portal are opposite from the reference frame of the portal (causing the body to be in dynamic equilibrium). To calculate internal stresses, you only take the forces acting in a single direction through a plane, which in this case is 1g.
This isn't intuitive, but is similar to comparing a car crashing into an immovable wall to a car crashing into another car (that has equal speed and amass, opposite direction of travel). Both cars are equally damaged (and if you think otherwise you need to study basic physics). The will apply to this case and a person standing on the ground. A person of the ground has 1g acting down from gravity, and 1g acting up from the ground. You know that the internal stresses on a person in this case is 1g, and the same applies to the portal's case (with the opposite force simply being caused by gravity).

>>9052172
I see your point anon but I dont think the change would be all that excruciating. Imagine diving into a pool but the pool is made up of air and after a while you would just float back the surface of the pool. It would be more like you are launched up into the air at terminal velocity and you start losing momentum due to gravity.

>>9052172
that video game is cancer

"if" portals could exist they would:
1) need to be stationary relative to eachother
2) need to be oriented spatially the exact same direction

that's the only way that the laws of physics don't break and create paradoxical scenarios.

again, for emphasis, that game is cancer and you should not post content related to it on this board.

>>9052617
They don't need to do either of those though.

>>9052622
>They don't need to do either of those though.
if you think about it long and hard enough you will understand that for them to "actually exist" they would in fact need to exhibit both those qualities.

>>9052627
Please name some of these paradoxical scenarios.

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>>9052617

>>9052635
conservation of momentum
>>9052644
videogame physics ≠ real physics

>>9052649
Violation of conservation of momentum does not mean the system produces paradoxes.

>>9052678
what is your definition of a paradox? My use of the term was meant to communicate that the implications of the assertions produce contradictory/incompatible scenarios.

>>9052696
In this context I would consider a paradox to be a violation of the classical principle of relativity, i.e. that the situation cannot be reconciled with Galilean transformations.

>>9052717
>Galilean transformations
that would preserve the orientation requirement I mentioned and in order for their to be an agreement from all reference frames on the momentums the "portals" need to be stationary relative to one another.

>>9052729
No it doesn't. In the simplest model a particle enters portal 1 with a velocity [math]\vec{v}_i[/math] and emerges from portal 2 with [math]\vec{v}_f = R \left( \vec{v}_i - \vec{v}_1 \right) + \vec{v}_2[/math], where [math]\vec{v}_1[/math] and [math]\vec{v}_2[/math] are the velocities of the portals and [math]R[/math] is an orthogonal matrix representing the orientation of the two portals relative to each other. The equation is invariant under boosts (i.e., adding a constant velocity [math]\vec{u} [/math] to all existing velocity terms) and rotations (as long as [math]R[/math] is transformed as well under the usual tensor transformation).

>>9052172
They would just decelerate at 1g

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>>9052748
how is momentum conserved here?

>>9053007
It's not.