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2023-11: Warosu is now out of extended maintenance.

/sci/ - Science & Math

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6441844 No.6441844 [Reply] [Original]

>> No.6441848

>>6441844
It's A.

>> No.6441850

A.

Because nothing is imparting energy on the block.

>> No.6441854

>>6441850
Portals may impart energy on the block. The question is of course unanswerable, as it includes made up physics with ill defined properties.

>> No.6441859

>>6441854
It's B. If the cube were going to the orange portal, it would be the same relatively form the cube's perspective if the orange portal were going towards it.

>> No.6441863

>>6441850
Yet the cube is being pushed outside the portal, otherwise it wouldn't come out.
Thus the portal is given velocity.
Therefore B is the most rational choice.

>> No.6441866

>>6441854
>The question is of course unanswerable, as it includes made up physics with ill defined properties.
This

>> No.6441867

I think it has to be B. Relative to the orange portal it is moving fast. I don't think it matters that it isn't moving relative to the blue one.

>> No.6441868

Is there a net force acting on the box? No. It's A you dickheads.

>> No.6441869

>>6441866
>>6441854
Think of it as a wormhole.

>> No.6441875

If it was A, how would it look like in an animation? If part of the block goes through the portal, how will the rest of the block go in when the first part has zero velocity? It has to be B.

>> No.6441876

>>6441868
What if passing the portal induces a force on the cube?

>> No.6441877

It's B. Even with whatever funky laws of physics you'd need in order to have portals, they're still going to be computed locally. A is computed non-locally.

Also, from the perspective of the cube, the stuff it sees inside the yellow portal is approaching it at the speed the portal is going. That's how fast the cube is going relative to it's nearest neighbors once it hits the far side of the portal.

>> No.6441886

>>6441876
Then yes, but I can't see how that would happen. It seems like the box is remaining stationary whilst the direction of gravity rotates around. No net force means no movement.

>> No.6441887

PORTALS CAN'T BE MOVED DICKWIT!

if they are attched to a surface, the moment the surface move the portal dissapears

>> No.6441890

>>6441887
But the Earth is always moving.

>> No.6441895

>>6441890
but the surfaces in the videogame aren't on earth, they are in a virtual program that does not move

>> No.6441909

You guys are idiots. The scalar of the momentum of the object relative to the portal that it passes through is conserved. So B.

>> No.6441913
File: 59 KB, 903x451, portal explanation.png [View same] [iqdb] [saucenao] [google]
6441913

It's B. See pic.

>> No.6441914

>>6441890
>what is relativity

>> No.6441915

>>6441909
>The scalar of the momentum of the object relative to the portal that it passes through is conserved. So B.
Because surely you have verified it with real-world portals? It's like saying a time machine would work like this or like that, until we build one anything is possible. A, or B, or neither. /thread

>> No.6441918

>>6441915
>What are thought experiments
Don't respond to this thread if you think it doesn't matter.

>> No.6441919

>>6441915

There is a difference between self-contradictory and merely impossible. (Everything self-contradictory is impossible, but not everything impossible is self-contradictory.) Both A and B are impossible, but only A is self-contradictory.

The WAY in which they are impossible is that they require a modification to the laws of physics, but that specific modification is already a given with the existence of portals.

It's B.

>> No.6441927

>>6441890
It's a game, dude.

>> No.6441942

It's neither, idiots.

>> No.6441950

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

>> No.6441952

What is the stand and the piston thing made out of? because if they hit hard enough energy would go to the cube and send it flying, otherwise it would A.

>> No.6441964

>>6441918
You don't understand, until we build such a portal we have no idea how it might function, hence the answer could be A, or B, or neither. All the answers everyone gives are according to how they think it might function. This is why this thread is always useless.

>>6441919
>Both A and B are impossible
They might be possible
>but only A is self-contradictory
Because?

>> No.6441982

I guess in one frame of reference it's moving, while in the other it's stationary. So perhaps it only has velocity (from the blue perspective) while it passes through the portal, then ceases to have any velocity the moment it has passed through. But then that would defy the laws of physics, so I suppose I'd have to say B.

>> No.6442000

>>6441964
>They might be possible

They violate both causality and conservation of energy. So they're only "possible" in the sense that literally anything is "possible" if we're wrong about everything we think we know about physics.

>Because?

see >>6441913

>> No.6442008

>>6442000
>They violate both causality and conservation of energy.
You don't know how the portal is powered so no they don't necessarily violate these principles.

>see >>6441913
Or it could be the portal is regenerating the object any way it pleases without imparting it any velocity.

>> No.6442012

>>6442008
>Or it could be the portal is regenerating the object any way it pleases without imparting it any velocity.

Seems like you didn't read the explanation.

>> No.6442019
File: 11 KB, 259x200, 1353017796624.jpg [View same] [iqdb] [saucenao] [google]
6442019

Imagine that it is like sticking your finger out the window really fast. Does your finger go flying off into space? No, but it does cross the threshold of the window pretty quickly. So the correct answer is A

>> No.6442023

>>6442019

fuck off you idiot

>> No.6442024

>>6442012
Seems like you are assuming that your explanation is based on how the portal works.

>> No.6442027
File: 61 KB, 225x186, 1315798698624.jpg [View same] [iqdb] [saucenao] [google]
6442027

>>6442023
eat a dick, and explain to me why i'm wrong
pic related

>> No.6442030

>>6442024

Please read the explanation. There is nothing about how the portal works, just avoiding self-contradiction.

>> No.6442033

>>6442027
see
>>6441913

>> No.6442043

>>6442030
I read your explanation don't you hear. You are assuming the cube must exit the blue portal at the same rate it enters the orange, because that's how you think these portals would work. I'm telling you the blue portal could very well regenerate the cube any way it pleases after it has completely gone through the orange portal. If you think the cube is instantaneously sent to the blue portal faster than the speed of light, then you are assuming something more.

>> No.6442048

>>6442043
>You are assuming the cube must exit the blue portal at the same rate it enters the orange, because that's how you think these portals would work.

That's not an assumption. That's an observation from the game. You don't disappear and then get regenerated. You move smoothly through and can do so at any speed.

>> No.6442051

>>6442019
Are you this stupid? Of course your finger won't fly off since it is attached to your fucking arm.
The cube isn't attached to something that prevent it from flying, so it will fly.

>> No.6442059

>>6442048
> You don't disappear and then get regenerated. You move smoothly through and can do so at any speed.
How would you notice any difference if the portal regenerates you faster than the time it takes for your eyes/brain to construct two successive images? (which is in the order of 10ms or so)

>> No.6442063

>>6442033
I will admit that is a good explanation, but consider this: When the portal comes slamming down on the block, the block will still be sitting stationary in the first frame of reference on the platform. So when it goes through the portal, one side will still be touching the platform in the first frame of reference. What that image implies is that after moving through the portal, it will lift it off the platform, which makes no sense

>> No.6442070

>>6442063
It will lift off since it is MOVING through the portal, and there's no reason for the cube to suddently stop moving after it moved through the portal.

>> No.6442076

>>6442070
PART OF IT WILL STILL BE SITTING ON THE PLATFORM YOU FUCKING FAGGOT, HOW CAN IT STAY IN RELATION TO THAT BY FLYING OFF INTO FUCKING SPACE??!

>> No.6442088

>>6442076
but as soon as more than half of the mass of the cube is through the portal the gravitaional pullon the other side will pull the cube to the right and thus aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
A

>> No.6442094

>>6442076
You admitted yourself that the cube moves through the portal.
Once the cube is completely passed, it doesn't lose all of its velocity all of a sudden, does it?
Hence why it continues moving up in the air, before falling down thanks to gravity.

>> No.6442099

>>6442094
What fucking velocity?
THE CUBE IS STATIONARY

>> No.6442104

>>6442059
What are you talking about? The actual process doesn't matter. What matters is the cube has to have some velocity relative to the blue portal.

>>6442063
>which makes no sense
Why? It does make sense.
Actually, if you stop the orange portal halfway through, the block would STILL lift from the platform.

>> No.6442109

>>6442099
WELL IF IT'S STATIONNARY, HOW DOES IT PASSES THROUGH THE PORTAL?
Retard.

>> No.6442112

>>6442109
The piston moves.

>> No.6442114

>>6442099
It won't be stationary once the part near the blue portal starts pulling on it

>> No.6442115
File: 151 KB, 427x427, 1351484573165.jpg [View same] [iqdb] [saucenao] [google]
6442115

Neither is right.
Depending on what laws of physics you consider either option looks valid while the other seems to be impossible.

Let's start with option A:
If you are considering conservation of momentum, then option A appears to be correct, while option B violates conservation. (inb4 but the platform with the orange portal stops and the box shoots out) yes but 1) the momentums are in different directions 2) the magnitudes can be different.
So in this view, A is right, and B is wrong

Now, let's look at option B:
If you are considering the process of the box passing through the portals you will see that it _must_ have some velocity as it exits. For example, divide the box into 2 connected pieces. The first piece must exit the blue portal at exactly the same speed as the second piece is entering the orange portal (otherwise the object would become compacted, which it doesn't) you can divide the box up indefinitely to realize that every piece must exit the blue portal a speed equal to that of the falling orange portal. This implies that the box would be shot out at that same speed.
So in this view, B is right, and A is wrong


All this does is to highlight the fact that portals could never work this way. Something would have to be different.

>> No.6442116

>>6442112
i think you mean portal, but yeah
>>6442109
FUCK YOU FAGGOT

>> No.6442118

>>6442115
A is self contradictory and your argument is wrong.
Portal give energy to objects passing through, conservation doesn't apply.

>> No.6442120

>>6442112
So the cube emerges off the portal with no velocity?
Top lel.

>> No.6442121

>>6442104
>What are you talking about? The actual process doesn't matter.
Then indeed you still haven't understood what the fuck I'm talking about. Of course the process matters that's precisely the point. I thought we were talking about hypothetical portals, now if you're referring to the portals from the eponymous game, and if you're saying that in the game, when you go into one portal with a velocity V you go out of another portal with the same velocity V, then yes the answer would be B. Assuming also that the universe in that game works the same way than ours.

>> No.6442122

>>6442121
>when you go into one portal with a velocity V you go out of another portal with the same velocity V, then yes the answer would be B.
Well ok then we agree.

>> No.6442129

>>6442118
>Portal give energy to objects passing through, conservation doesn't apply.

Have you even taking a high-school level physics class?
Conservation of momentum ALWAYS applies anon, doesn't matter what you're doing with energy

>> No.6442130

>>6442129
>Conservation of momentum ALWAYS applies anon
Not when there are external forces

>> No.6442133

>>6442129
>rockets don't exist
You are THIS retarded.

>> No.6442136

>>6442130
>>6442133
oh geez, is /sci/ really this fucking uneducated?

>momentum conservation is not a general property of the universe
>rockets don't conserve momentum

what the fuck happened to this place? These are the dumbest comments I've seen on here in a while.

>> No.6442141

>>6442136
>this whole post
>someone thought it was funny, typed it out, and hit "send"

>> No.6442143

>>6442136
If you took basic physics classes you would know that the momentum of an object is conserved when no exterior forces apply on it.

>> No.6442144
File: 668 KB, 1000x750, 1386897204004.jpg [View same] [iqdb] [saucenao] [google]
6442144

>>6441869
>think of it as a wormhole
Wormholes are not properly defined in physics, due to the recent breakthroughs in Quantum Physics. It's undefined.

mfw

>> No.6442145

>>6442133
>>6442136
You two are the retards. The rocket itself doesn't conserve momentum, the system rocket+propellant expelled does. Obviously the momentum of a car is not conserved when it goes from 0 to 100km/h, because guess what, m*0 != m*100

>> No.6442146
File: 75 KB, 432x284, hole-in-the-wall-show.jpg [View same] [iqdb] [saucenao] [google]
6442146

>>6441844
its A
Imagine you're running at a wall with a hole in it, and you jump through, you would essentially look like image B in OPs pic. However if the wall were to somehow be able to move at you, like in that one japanese game show, then you would simply look like A in OPs pic.

Portals are really just holes in space, they act exactly the same as a hole in a wall just each side of the hole can be placed where ever in space.

>> No.6442148

>>6442143
As long as those forces do not compensate of course.

>> No.6442153

>>6442146

gr8 b8 m8

>> No.6442155

>>6442145
>You two are the retards
Don't lump me in with that idiot. I never said that a single object by itself always has momentum conserved.

He's the one saying momentum conservation depends on what system you are considering... YES it does, but that is NOT a general rule, that's just a simplification that allows you to ignore the rest of the universe. But as a universal property momentum IS always conserved.

/sci/ is fucking just sitting there while some highschools tell me momentum conservation doesn't always apply.
I don't even know what to do anymore. This thread is incredibly depressing.

I seriously hope I'm being trolled

>> No.6442158
File: 28 KB, 668x190, HoleInTheWall-yellow.jpg [View same] [iqdb] [saucenao] [google]
6442158

>>6442115
You have to consider the velocity as relative. If the portal is moving towards the block then conservation of momentum would in fact make the block continue to move relative to the contents of the portal and thus alternative B is true. If I move a wall with a hole towards you it keeps going even after you go through. If I move the whole universe towards you then it will also keep going.

Saying that the momentum are in different directions would imply that there is some type of objective frame of reference here, and there clearly can't be. You have to consider it from the perspective of the block, and the block will keep going like in B.

>> No.6442159

>>6442155
>momentum conservation doesn't always apply.
You realize we are talking about a hypothetical device known as portals right? They obviously violate momentum conservation, even when immobile.
hint: momentum is a vector quantity

>> No.6442161

>>6442146
This analogy is flawed because in op pic one portal is moving while the other stands still.

>> No.6442167

>>6442153
are you retarded?

>> No.6442168

>However if the wall were to somehow be able to move at you, like in that one japanese game show, then you would simply look like A in OPs pic.

No it freaking wouldn't the wall would keep going unless it decelerated

>> No.6442169

>>6442155
>But as a universal property momentum IS always conserved.
That doesn't mean jack shit, in any sub-system of the universe subjected to forces the momentum of the system is not conserved, how nice for a "universal property".

>I seriously hope I'm being trolled
I think you're the one doing the trolling, either that or you are very, very stupid

>> No.6442170

>>6442155
The momentum of the whole system is conserved.
You know nothing of the momentum of portals and whatever is powering them, there is no point in applyijng momentum conservation here.

>> No.6442178

>>6442167

no

>> No.6442182

>>6442161
It doesn't matter, the argument is still the same. Portals are just able to split each side of the hole, nothing about the physics changes

>> No.6442191

>>6442182
>Portals are just able to split each side of the hole
That's why B is correct.
Continue your wall analogy. After the wall passes you, you are moving away from the wall in its reference frame.

Same thing for the portals, the cube will be moving away from the blue portal in the blue portal reference frame.

>> No.6442192

>>6442182
>It doesn't matter

Of course it matters. You've got two frames of reference instead of one. see >>6441913

>> No.6442199

>>6442182
It does matter:
In your example, the speed of the cube relatively to the second half of the hole is not equal to zero.
In the example of the portal, the velocity of the cube relatively to the second portal must be non zero too, so it is moving up.

>> No.6442208

>>6442191
no, if we're talking about reference frames then when the wall from the japanese game show passes over someone you could easily image the wall is not moving and the person has the negative velocity of the wall. But that's not actually the case since the person has no velocity, same with the block sure you can make it look like the block has some velocity with regards to the portal but thats only because your frame of reference is the portal, which is moving, and thus your frame of reference is wrong.

>> No.6442212

>>6442208
>But that's not actually the case
You seem to have trouble with the concept of reference frames.

>> No.6442215

>>6442208
Momentum isn't conserved when passing through a portal.
Momentum is a vector, not a scalar.

>> No.6442216

>>6442212
draw some force diagrams

>> No.6442217

>>6442216
>force
Irrelevant, you don't know what kind of forces the portals apply.

>> No.6442283

>>6441844
A. At the end of the movement, the portal is not moving relatively to the cube (it decelerates when it stops against the platform the cube was originally on.)
The fun part is, that the cube would move through the portal fast first, and then it would decelerate to a complete stop, followed by that "plop" fall.

>> No.6442284

>>6442146
>>6442178
>I-I was only p-pretending to be r-retarded!

>> No.6442290
File: 54 KB, 600x500, 1299280610537.jpg [View same] [iqdb] [saucenao] [google]
6442290

Well if the cube's linear momentum is maintained as it passes through the portal (as the game suggests) then of course it's option A.
I can't see the other answer being logical since that would basically require the cube to acquire the acceleration of the piston that contains the portal without any contacts, since contact with the portal is impossible (it's a distortion in space/time I guess).

>> No.6442306

>>6442116
piston
the portal is stationary

>> No.6442309

>>6442283
>>6442290

No, it's B. See >>6441913

>> No.6442315

>>6442309
Well that's a good explanation but I can't imagine it. And due to the non-physical nature of portals the only way to prove one or another would be testing in the game of course.
If this was a test both answers wound be totally plausible if justified correctly I guess.

>> No.6442321

>>6442283
>The fun part is, that the cube would move through the portal fast first, and then it would decelerate to a complete stop, followed by that "plop" fall.

And what would cause it to decelerate? The part of the cube already through the portal has a lot of momentum. And since it's already through the portal, no funky physics applies - it has to conserve that momentum somehow.

It has to be B.

>> No.6442325

>>6442290
>would basically require the cube to acquire the acceleration of the piston

It doesn't have to acquire anything. It is already moving relative to the entry portal.

>> No.6442327

>>6442325
So? What counts is the movement of the object, not the portal. The portal is only a distortion of space, it doesn't magically generate energy or force.

>> No.6442334

>>6442327
>What counts is the movement of the object, not the portal.

That's the same thing. Motion is relative.

>> No.6442347

>>6442334
You change the reference you use but the absolute energy and force being applied in the object is maintained. Energy and momentum conservation are always applicable.

>> No.6442395

>>6442347
Not when it passes through a portal. Glados lied to you.

>> No.6442424

>>6442325
Hence why it's A.

>> No.6442430

NO.

NOT THIS FUCKING THREAD AGAIN.

WE ANSWERED THIS SHIT ALREADY.

>> No.6442433

>>6442424

wat

>> No.6442450
File: 3 KB, 300x57, image.jpg [View same] [iqdb] [saucenao] [google]
6442450

Perhaps we should introduce Bill Nye to Portal, and then ask him to solve this question.

Or people at the LHC. If anyone can answer this, it'll be them.

>wow
>much dbationa
>many disagreement
>so unsolved

>> No.6442464

>>6442043
in the game, it is stated that anything that enters portal A exits portal B at the same rate

>> No.6442469

>>6441844
>>>/v/

>> No.6442492
File: 79 KB, 720x479, 1362259649327.jpg [View same] [iqdb] [saucenao] [google]
6442492

>>6442450
their answer

>> No.6442508

Only A can be right, but it also can be wrong.
The portal can't apply force to the cube as it basically functions as a hole. If you did this but with a box missing one side instead of a portal no force would be exerted by the box onto the object.
The reason the cube slides is because of gravity and it's new angle by leaving the blue portal.

But A can still be wrong. If gravity doesn't silly enough pull the box could just get caught on the side of the portal. For this think of angled blue as being slowly dropped into the box. The platform the box is on would angle to fit into the blue angle but would still be underneath it thus making the who knows how thin portal function as a wall to hold the cube at the angle instead of it sliding out.

>> No.6442504

>>6441890
What are reference frames

>> No.6442519

>>6442508
how does the box move if there is no force?
how does the box exit the portal if it doesn't move?
low quality bait is low

>> No.6442526

>>6442508

1/10

>> No.6442530

>>6442519
Gravity is the force that makes the cube slide out. Look at the angle of blue. It would just be like setting the cube down into the ramp. Gravity would take over and pull it down the ramp.

>> No.6442532

>>6442508
>The portal can't apply force to the cube as it basically functions as a hole

This is incorrect, even for ordinary portals. Applying F=dp/dt shows this immediately. When an object enters one portal and exits a second that points at a different angle, the object changes its direction of momentum. If the object changes from momentum p to p', p'-p = delta-p. If the object takes time t to pass through the portal, the average force on the object is F = delta-p/t.

Portals also move objects from one place to another. Mass decreases on one end and increases on the other. If an object with velocity v is moving into a portal, and the mass is going in at a rate dm/dt, then the force of the portal on the object is v*dm/dt. There is a corresponding and opposite force on the other side (here, dm/dt is positive, since mass is being added).

The sum of forces by the two portals will be a net force, giving total net impulse (integral of force over time) equal to delta-p.

>> No.6442559

>>6441844
I think about it this way:
1) consider the orange portal as a simple hole
2) add simulate the forces applied to the blue-portal side above the orange-portal side (in your example we have to consider gravity: an easy way to do this is to put a suction duct next to the orange portal in such a way that it applies a pulling force to the cube only after it passes the hole)
3) see what happens
4) add the magical teleportation power of the portals without changing the outcome
This seems the most logical way to look at it and it would yield the A result (assuming the piston stops when it reaches the pillar)

>> No.6442609

Lets say the piston moves at a velocity of 20 kilometers per second.

It SLAMS down onto the stationary platform.

As soon as the piston hits the platform, all energy is lost (Or if the piston can only extend so far). How would it transfer any energy to the cube?

It would not and it cannot.

A portal, in theory, is simply the shortest method of moving from point A to point B.

They practically overlap.

No energy is applied (to objects entering the portal), only energy is saved by making the two points practically overlap with one another making the energy required to travel minimal.

>> No.6442629

>>6441844
Not reading 108 posts.

In the referential of the orange portal, it's as if the whole "world" was moving towards it at great speed( including the cube).

Thus the cube will fly out.

Checkmate.

>> No.6442635

>>6442609
how does the cube move if there is no energy transfer?
You do realize that the cube has to move to enter the portal and exit from the other side.

>> No.6442638

>>6442609
>Lets say the piston moves at a velocity of 20 kilometers per second.

Which means that the block passes through the portal at 20 km/s, which means the answer is B.

>> No.6442651

>>6442635

In the case of moving portals, the only thing that is moving is the point to which the portal leads to.

(Orange Portal) moves at a velocity of 20 km/s towards cube on stationary platform.

The cube will reach the other side of the portal as it is apart from the platform

Since Orange portal now is shut (Piston is pressed against flat platform) Gravity enacts on it and it falls to the other side of the portal, which is the only side it can possibly be on.

The cube does not have to move.

Space moves itself to get the cube to Point B without the cube having to exert any energy.

>> No.6442660

>>6442651
see
>>6442638

>> No.6442669

>>6442660

>Which means that the block passes through the portal at 20 km/s, which means the answer is B.

But that's wrong.

>> No.6442680

>>6442669
if it enters at 20km/s what speed you think it will exit?
if it exits at 20, where does the speed vanish?
If it doesn't exit at 20 where does the rest of the cube go?

>> No.6442698

>>6442680
I'm >>6442559, try to think of the portal as a normal hole instead of a portal. The cube enters at 20 km/s, but after it passes the hole it certainly doesn't fly away: where does the speed vanish?

>> No.6442702

>>6442698
i'm
>>6442680
if thing enters at 20km/s what speed it exits?

>> No.6442709

>>6441844
Neither, portals can't be on moving walls.
1/10 made me respond.

>> No.6442710

>>6442680

The cube is motionless.

The only thing moving is space.

The portal represents a rip in space.

That rip in space moves towards the cube, and the rip can go over the cube, but it does not give the cube and velocity.

For instance, your mother's pussy (portal) slams down on my cock (cube).

My cock has no initial velocity, but it is now, by the power of the pussy (assuming it's a portal), in a different place.

Fuck you.

>> No.6442716

I actually think that it is a. I see no difference in the physics than if there were no portals, and there was just a hole in the platform. The portal would envelop the cube at a speed, but because the cube is not moving in relation to the overall system it would just plop out of the blue portal.

>> No.6442712

>>6442710
>The cube is motionless.
how does it exit the other portal then?
You do realize that it is moving when it comes out, you can't be that retarded.

>> No.6442720

>>6442712
Because gravity is pulling in a different direction on the other side of the portal. it would be pulled through and downward by gravity.

>> No.6442721

>>6442712

It only moves because of gravity, shit head.

You can stand between two portals and there is no force applied to you.

God damn..

>> No.6442724

>>6442720
>>6442721
before it goes to the other side
how does the first atom go to the other side?
And even if it's only gravity how does that explain it exiting at 20km/s?
You do realize that it moves entirely to the other side at the same speed the space goes out on the other side

>> No.6442727

>>6441844
B - Conservation of energy.

Although this appears to be tenuous reasoning in the world of portals...

>> No.6442729

>>6442724


Yes, if you took a speed gun and aimed it at the cube from the blue portal, it would read that the cube is going 20 km/s due to inertia, but LOW AND FUCKING BEHOLD WHEN THE PISTON STOPS

SO DOES THE CUBE

HOLY SHIT

WOW

SCIENCE

>> No.6442733

>>6442729
and how you think that happens?
Cube is moving at 20km/s where does the speed go? Things don't stop just because you want them to, it's a hole it can't stop the cube.

Reference frames are hard but don't go mad if you don't understand them.


Just look at the exit portal
first there is nothing
then there is cube coming trough at 20km/s
then it continues on that flight path

It doesn't stop just because it exits the portal, there is still conservation of energy and momentum going on outside of portals.

>> No.6442740

>>6442727
The piston would impact the pedestal. Energy would be transferred to the pedestal not the cube.

>> No.6442757

>>6442733

The piston has all the speed.

The cube has none.

>> No.6442763

>>6442757
g8 b8 m8 r8 8/8

>> No.6442770

>>6442740

The cube already HAS energy in the reference frame looking through the exit portal.

>> No.6442776

>>6442729
>if you took a speed gun and aimed it at the cube from the blue portal, it would read that the cube is going 20 km/s

Great! And what if you kept that speed gun aimed through the portal? When the cube is halfway through, how fast is it moving then? It still must be 20 km/s, correct? And also when it's 90% through? and 99.99999% through? So why, when it's 100% through, would all that mass suddenly stop?

>> No.6442779

>>6442776
Because the portal(orange) has stopped. The portal provides the movement, not the cube itself.

>> No.6442781

portals dont real btw

>> No.6442787

>>6441863
Not exactly. It is impossible to deduce whether A or B is correct without any data. I assume that most of the Kinetic energy would be absorbed by the pedestal while the cube would be barely affected. Therefore A would be the more reasonable choice.

>> No.6442845

>>6442729
To understand why this is wrong, consider the following modification to the problem: there is no gravity, and no platform. The piston descends at 20 km/s and never stops. The cube passes through the portal. After the cube has passed through the portal, what speed is it moving at when it exits, A) 0 km/s or B) 20 km/s?

Clearly, from the first moment that the cube begins to emerge from the blue portal, its front edge must be moving at 20km/s, since it has to move out of the way so more of the box can enter. This speed must persist until the moment the last atom of the box exits. Now, the whole box has just exited, and has been moving at a constant speed of 20 km/s out of the blue portal for the last few moments. It's done exiting--does it suddenly stop? Why?

>> No.6442862

>>6442779
>The portal provides the movement, not the cube itself.

That's meaningless jibberjabber. What is Newton's First Law? The cube is moving at 20 km/s. It needs something to stop it if it's going to stop.

>> No.6442886

>>6442862

But the cube ISN'T moving...

It's the piston above the cube, not the platform that is below it that is moving...

I hope that /sci/ isn't this mentally inept..

>> No.6442898

>>6442845

The piston makes no contact with the cube, ever, therefore, it is impossible for there to be a transfer of kinetic energy. It is common sense.

If the cube sat ontop of a piston that rammed itself up into a portal, THEN the correct answer would be B due to inertia.

>> No.6442909

>>6442886
>doesn't even understand frames of reference

>> No.6442910

>>6442898
>The piston makes no contact with the cube, ever, therefore, it is impossible for there to be a transfer of kinetic energy

So it is impossible to transfer kinetic energy without physical contact? The earth doesn't contact an apple when it accelerates it downward. A charged particle will repel another of the same charge from a distance, accelerating both apart. So why can't a portal exert a force on the cube?

We already know that ordinary, stationary portals apply forces on things that pass through them--for that argument, see >>6442532

It seems that stationary portals are a special case, in that they only accelerate objects in directions perpendicular to their motion, rotating their momentum vectors while leaving the magnitude the same. But we have no reason to assume that moving portals fall under the same special case, and every reason to think that they *will* end up changing the magnitude as well as the direction of the box's momentum.

>> No.6442924

>>6442910
Portals also charge things with gravitational potential energy too all while not touching the thing at all

this is a troll thread anyways

>> No.6442929

>>6442910
Not him but I don't think it's accurate to say that the portal changes the magnitude of the box's momentum so much as it changes the reference frame of that momentum. I agree with your overall argument though.
In support of that argument, I think it's worth taking into consideration the surrounding air, assuming a case where the box isn't in a vacuum. A moving portal would have to transport a column of air moving at the same speed as the portal itself.

>> No.6442933

>>6442924
>this is a troll thread anyways

True, but I enjoy the actual physics discussion. It's like finding yourself in a new world where the laws of physics appear the same, but there's this new phenomenon that you have to make sense of. So your task is to come up with a coherent, simple theory that fits with what you see and predicts what will happen in cases you haven't yet observed. Sort of like practice for doing real science.

>> No.6442943

>>6442933
It's like 2nd grade high school stuff at max though pretty much instantly obvious to any adult

>> No.6442975

>>6442929
>I don't think it's accurate to say that the portal changes the magnitude of the box's momentum so much as it changes the reference frame of that momentum

I understand your point and that's an OK way of thinking about it, but it's also dangerous. The question we should be asking is what happens in the lab frame. If you try to change frames of reference in the middle of an experiment, you have to be really careful or you run into all sorts of problems.

As an example, I've given a little thought to the question of more general movements of portals. It turns out, accelerating portals should cause objects that are partway through them to accelerate.

Take a rod that is in the center of a portal, with equal masses sticking out on each side. Everything is measured in the lab frame. Call the ends A and B. If you accelerate the portal towards A, the A end will start accelerating away from the portal as it is swallowed, while the B end will also accelerate away from its end of the portal. At any point in time, v_A + v_B == v_portal, and the balance of mass determines how the velocity is divvied up.

Another interesting case is when the portal is accelerated perpendicular to the rod--here, each end of the rod is accelerated radially, and they each end up moving at 1/2 the speed of the portal--so if the portal moves down at v on side A, the rod moves down at v/2 on side A, and up at v/2 on side B. This persists until the rod hits the edge of the portal, and stops.

>> No.6443005

what would happen if the orange portal stopped half way down the cube? would the cube be sucked through the portal? ripped in half?

>> No.6443025

>>6443005
Half the cube would be through the orange portal, half would be through the blue portal. As if you were standing in the middle of an open doorway.
Think of the orange portal as an open doorway flying towards the cube and the blue portal as the other end of the doorway.
A would be correct in this case as no force is exerted on the cube, although the orange portal would become blocked off by the pedestal, which would cause the cube to fall down the slope as shown in A due to gravity. The force would be absorbed by the pedestal.

>> No.6443084

>>6443005
If the orange portal was moving at speed v then dropped to speed 0 the moment the cube was halfway through, the cube would exit the blue portal at speed v/2--each end would be suddenly accelerated when the piston stopped.

>> No.6443120

>>6441844
It's definitely not B, but it is probably not A.

>> No.6443129
File: 141 KB, 600x500, otq2okrm.png [View same] [iqdb] [saucenao] [google]
6443129

>>6442290

>> No.6443130
File: 1.81 MB, 1600x1186, Homemade_hula_hoops.jpg [View same] [iqdb] [saucenao] [google]
6443130

I imagine portals as hula hoops connecting different dimensions. Move a hoop through something really fast, that thing will stay stationary no matter what.

This will help some of you understand the idea around option A.

Also, portals don't exist.

>> No.6443141

Just an open doorway, right. A hole. A hula-hoop. Only with its two sides in <span class="math">completely~different~inertial~reference~frames[/spoiler].

Now that I think about it, both A and B require a phantom force to act on the cube in one way or the other. There's no right answer to this. It's a poorly defined system.

>> No.6443327

ITT:
Portals don't actually exist so...
>some of us assume the game's mechanics (Option A)
>some of us assume the most physically plausible mechanics (Option B)

Neither option is "correct", as the scenario is currently impossible, and thus the specifics which the theories depend on can't be known.

>it's 4chan so lets argue about it anyway.

>> No.6443390

>>6443327
>>some of us assume the game's mechanics (Option A)

Actually, someone set up this experiment in a designed test chamber. I remember seeing a youtube video of it in a previous thread. The game mechanics do option C: the block doesn't pass through at all. The portal acts like a brick wall, since moving portals were never implemented properly. The game allows them, but they're just cosmetic (in gameplay, you only use moving portals to send lasers through, which allows them to ignore the relative-velocity problem.)

>> No.6443500

B

>> No.6443515
File: 74 KB, 330x503, 1395911100425s.jpg [View same] [iqdb] [saucenao] [google]
6443515

a, fucking people are mixing portals up with a physical abstraction that affects the cube somehow. the cube is simply teleported, its coordinates shifted to a new plane. since we are not dealing with conventional physics here, the cube does not actually gain any sort of momentum, it only gets transported.
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

>> No.6443518
File: 49 KB, 300x345, 136593557547[1].jpg [View same] [iqdb] [saucenao] [google]
6443518

>>6443390
/thread

>> No.6443768

It's B, because the box has no velocity.

>> No.6443772

>>6443515

fuck off you fucking idiot

>> No.6443775

>>6443005
>what would happen if the orange portal stopped half way down the cube? would the cube be sucked through the portal? ripped in half?

Either one, depending on the physical integrity of the cube. The part that's the cube is already moving, so it's momentum will try to pull the rest of the cube through. If it doesn't break, the cube will be launched at half speed.

>> No.6443776

>>6442975
>The question we should be asking is what happens in the lab frame.

In this case, they are BOTH the "lab frame."

>> No.6443898

>>6443390
You can't make portals on moving surfaces

>> No.6443966

>>6442120
you don't know how portals work. The portals don't have any velocity they are simply a window in space time. The cube isn't moving it has no velocity and obviously the portal isn't increasing the velocity of whats on the other side, it's simply moving quickly towards the cube.

A would happen it's the same thing that would happen if you dropped a window frame over the cube.

>> No.6443973

>>6443966

fuck off you fucking idiot

>> No.6443977

>>6443973
you, are a fucking idiot. If the portal wasn't in a completely different place and was just say, directly on the other side of the moving piston what the fuck would happen? It would function exactly like a huge hole in the piston, so what the fuck would make you think that moving the hole would change the results?

>> No.6443993

From the moving portal's frame of reference, is the cube who has a velocity, so imo it's the option B. Portals like these don't exist, though, and as someone stated before, you can't have a portal in a moving surface, but I'd still say that if there was the ability to have this thing working, the most appropriate case is the B one.

>> No.6443996

>>6443977

see >>6441913 if you're not just trolling

>> No.6444023

>>6443993
>From the moving portal's frame of reference
Could you fucking nerds stop this shit? The fucking cube isn't moving. The portal is. Look at the goddamn picture.

>> No.6444032

>>6444023
>can't into reference frames
Don't worry they teach that in high school so don't worry it will come in few years.

>> No.6444039

>>6444023
If the cube isn't moving, how is it coming out of the second portal?

>> No.6444041

>>6444032
>if someone's running at you you gain kinetic energy
seems pretty legit

>> No.6444047

>>6444041
Relativity of motion and shit, is the portal moving or is everything moving towards the portal?

>> No.6444046

>>6444041
>still doesn't understand reference frame
In fact you do gain kinetic energy from the runners reference frame as there is no objective movement
Again they teach this in high school so don't worry you should stop shitposting though.

>> No.6444050

>>6444049
kek

>> No.6444049

>>6444047
Of course the portal is moving, look at the fucking picture. There are lines and shit to make it clear to your retarded ass.

>> No.6444076
File: 638 KB, 960x751, 47MUF.png [View same] [iqdb] [saucenao] [google]
6444076

>>6444049
are you trolling by any chance?

>> No.6444083
File: 70 KB, 669x659, unforseen_obs.png [View same] [iqdb] [saucenao] [google]
6444083

>>6444076
saved, have this in return:

>> No.6444284

>>6443776
No, they're really not. The "lab frame" should uniquely identify the velocity of any given object. The frame of the moving portal is not the frame of the stationary one. At the very least, the moving portal is moving in the lab frame, but stationary in its own frame.

What we want is an expression that is invariant to Galilean transforms, so we can choose whatever frame we wish. Now, portals that face different directions rotate velocity vectors, so for simplicity, I'll give an equation for the case where the blue portal faces straight upwards.

If the (initial velocity, final velocity, orange portal velocity, blue portal velocity) are <span class="math">v_i , v_f , v_o , v_b [/spoiler] where up is positive for all velocities, then the following equation holds:

<span class="math">v_i-v_o = v_f-v_b [/spoiler]

Notice that because this is all in terms of velocity differences, it is invariant to Galilean transforms. It also, obviously, corresponds to case B, since motion is measured on both sides relative to the portal on that side. By the way, for the case where the portals are angled differently, we use their normal vectors n_o and n_b to write

<span class="math">(v_i-v_o) \cdot n_o= (v_f-v_b) \cdot n_b [/spoiler].

(If you have motion along the portal surface, that gets its own rotated expression, but that's beyond the scope of the discussion.)

>> No.6444453

>>6444445
hahahahaha

that's what you get for scripting :^)

>> No.6444445 [DELETED] 
File: 40 KB, 230x432, dental_plan_OC.jpg [View same] [iqdb] [saucenao] [google]
6444445

right answer is D for Dental Plan

>> No.6444456

>>6444453
lel
He got it with the wrong post
https://archive.foolz.us/sci/thread/6444444

>> No.6444481

Think about dropping a hula hoop over it, but gravity shifts 45 degrees (ish) to the right when it passes through to the other side.

>> No.6444657

is easy to prove the answer is a.

take a ring, representi g the 2 portals glued back to back, and drop it over an object that can fit through. did the object fly through the ring with high speed? of course not.

>> No.6444674
File: 5 KB, 304x288, blop.jpg [View same] [iqdb] [saucenao] [google]
6444674

A
think of it like this

>> No.6444680

also, could someone just open up the game and run a test on this.

>> No.6444689

>>6444680
You can't do portals on moving surfaces.

>> No.6444734

Yeah, but the second face of that ring (the blue one) isn't moving; the cube is the one who moves for the blue portal's frame of reference.

Come on guys, it's not that hard to understand

>> No.6444758

>>6441913
This is fucking stupid.

>> No.6444782

It actually makes much more sense than your whole life.

>> No.6444788

It is A. Because the velocity of the piston will only determine the time it takes for the cube to be teleported to the other side.

>> No.6444792

>>6444758

No anon, you are fucking stupid.

>> No.6444793

>Having enough power to move the self contained universe

>> No.6444795

>>6444788
>the time it takes for the cube to be teleported

What's a term for the rate of traveling a certain distance in a certain time? I'm drawing a blank!

>> No.6444826

>>6441913

whoever made this, is insanely stupid

>> No.6444837

>>6444795
The portal is just a hole. How can it transfer any energy? The only thing that act on the cube is the gravitational shift when it passes through.

Yeah it will move with a relative velocity to the orange portal.

And the perspective from the blue portal will be that the blue portal travels to the cube and to the other way around.

>> No.6445852

>>6444782
It doesn't.
These are game physics not real life ones.

>> No.6448213

>>6441913
4:23 PM - Watson: I see it like this:
4:24 PM - Watson: at 2 sec the system is at equilibrium... but just a little more
4:24 PM - Watson: and the cube would fall out of blue
4:24 PM - Watson: so it will be sucked in into orange
4:24 PM - Watson: while he seems to assume the block does not fall until fully past orange
4:24 PM - giraffe: Thought so too
4:24 PM - Watson: because there is only gravity acting on orange cube
4:24 PM - Watson: and gravity also on blue
4:25 PM - Watson: but the moment there is more gravity acting on blue cube
4:25 PM - Watson: the moment the cube will drop out of blue
4:25 PM - Watson: more gravity, due to more cubic area in the blue cube, thus more acting gravitational force
4:26 PM - Watson: >it's B it's B it's B
4:26 PM - Watson: are they trolling or several times smarter than me
4:26 PM - Watson: both is possible
4:26 PM - Watson: but I don't know which one

>> No.6448265

Wow, judging by the reduced amount of A answers, it DOES indeed look like /sci/ is smarter than other boards!

>> No.6448281

>>6448265
I answered A, so I think I'm smarter

>> No.6448290

A. We're not stupid. Go ask this shit on >>>/b/ if you want lulzxD

>> No.6448294

>>6444689
You can in Portal 2.

>> No.6448324

>>6448281
>>6448290

lel epig maymay

>> No.6448327

>>6444826

Kill yourself.

>> No.6448336

>>6448290
I think most of the people in this thread answered "B", and the sad thing is that they actually worked on their explanation.

>> No.6448338

>>6441876
Not possible.

The game states that portals conserve momentum.

>> No.6448367

>>6448338
Then the game lied to you.

>> No.6448541

>>6448336

It is B.

Consider the velocity of the cube relative to the exit when it is halfways out of the portal. Is it zero? Then it will not move out of the portal.

Is it any non-zero value? Then it will continue in a parabolic arc unless something reduces its velocity later.

>> No.6448576

>>6448541
Why would the cube have a velocity that high?
it's not even the thing moving

>> No.6448585

>>6448576

The cube is moving compared to the surface it is coming out of - the portals do not instantly teleport it from one place to another, they let the cube move from one place to another. Since the cube is changing its position relative to the surface it is coming out of, it as a velocity relative to that surface.

>> No.6450569

Comedme la polla todos

>> No.6451028

I know this is the oldest troll post on the board, but what if when the portal was moving down, it stopped halfway down the cube?
If B were to be true, would that mean half the cube would fly out? I don't play video games and Idk the given rules of portals

>> No.6451030

>>6451028
Yes. It would not necessarily* fly all the way out before being dragged down again, but it would lift from the platform.

*Depending on cube mass, local gravity and speed of moving portal

>> No.6451032

>>6451028
>>6451030

Wait, no. Not half the cube, the cube does not get cut in half at any point.

>> No.6451047

>>6451028
>If B were to be true, would that mean half the cube would fly out?

It would fly out at half speed. The part of the cube that has already emerged has momentum which carries the rest of it along for the ride.

>> No.6451126

>>6451047

Not actually true - as soon as the orange portal is moving, the cube has the full velocity it will later attain - if you look through the portal at the cube, it is moving towards you at that velocity. If the orange portal stops, the cube instantly loses that velocity again UNTIL cube enters into the orange portal (to any degree). At that point, the bit that has emerged through the blue portal has that velocity even if the orange portal stops moving, and it will drag the rest of the cube with it if it has enough K to move the entire cube, other wise the cube will lift and land again.

>> No.6451131

>>6451126

Addendum: The particular bit I disagree with is "half speed." While the cube will have half speed initially, it will lose speed as gravity works on the bit that still hasn't passed through the portal.

>> No.6451132

>>6451126
>if it has enough K to move the entire cube, other wise the cube will lift and land again.

You might want to think about this some more.

>> No.6451147

>>6451126

At the instant before the orange portal stops moving, half the cube is through the portal and half the cube is not yet through. Both have velocity V in the reference frame looking through the blue.

In the instant AFTER the orange portal stops moving, half the cube is through and velocity V and half the cube is not through and has velocity 0. However, since they are connected, there is an instantaneous transfer of momentum, and the whole cube exits the portal at V/2. It's basically an inelastic collision.

>> No.6451193

>>6451132

Sorry, badly formulated:

If it has enough K to move entirely through the portal before gravity drags it down again.

>> No.6451465
File: 1.88 MB, 226x200, 1370142061120.gif [View same] [iqdb] [saucenao] [google]
6451465

To everyone saying A, good job, you understand why A is right.

To everyone saying B, go grab a small object like a bottlecpa and a glass cup. Now, place the object or bottlecap on the surface of your desk, then take your glass and slam it onto the object or bottlecap with all your might, with the cup opening facing the object or bottlecap. Notice how the object or bottle cap doesn't move until you bat it out of the way because you just smashed glass all over your table or counter and likely lacerated your hand something fierce.

>> No.6451584

There's insufficient information to answer. The game states that momentum of the object passing through the portal is conserved (I believe explicitly at an early point in the first game, and heavily implied through several puzzles).

Since the cube is at rest initially, there is no force to act on it to launch it in the air. However, since the end portal is on an incline the force of gravity will act on portion of the cube that has passed through the portal.

It's immaterial whether or not the imaginary surface of the platform the cube is standing on is inclined or not, or if one microscopic fraction of the atoms in the cube are still on the other side. Gravity is acting on the portion of the cube which is through the portal already.

HOWEVER:
There is no information given about the coefficient of friction between the platform and the cube. If the static friction between them exceeds the force of gravity, the cube will simply sit there and not roll to the floor.

Alternatively, if the piston forcing down on the platform compresses it sufficiently, and it bounces, there might be enough rebound to impart momentum to the cube and launch it in the air as in B (assuming the piston ends its travel exactly at the surface of the platform).

>> No.6451616

>>6451584
>The game states that momentum of the object passing through the portal is conserved

GLaDOS states:
"You appear to understand how a portal affects forward momentum, or to be more precise, how it does not. Momentum, a function of mass and velocity, is conserved between portals. In layman's terms: speedy thing goes in, speedy thing comes out."

This is inaccurate, which is par for the course for GLaDOS. Momentum is a vector quantity, and is not conserved between portals, since portals can change direction. What is true is that *magnitude* of momentum does not change when going between portals that are at rest relative to each other.

For particles moving with speed V, the delta-V of the particle going through a pair of portals is a function of the delta-v of the portals, just as the delta-X of the particle is a function of the delta-x of the portals. Portals that are separated in position-space change the spatial position of particles that pass through them. Portals that are separated in velocity-space change the velocity of particles that pass through them.

>> No.6451621

>>6451465
2/10
Apply yourself.

>> No.6451694

>>6451616
Solid reasoning. I don't think it changes my assessment, though, unless we start to contemplate the magnitude of the velocity involved in particles passing through the portal...

>> No.6451735 [DELETED] 

>>6451694
Well, part of your reasoning is muddled by trying to include gravity, friction, the normal force of the platform, etc. It's best to work this out the way a physicist would:

Consider a block of mass M in zero-g, moving at an initial velocity <span class="math">v_i<span class="math"> from the point of view of an external observer. An orange portal approaches at velocity v_o and collides with the block. The blue portal is moving at velocity v_b . The blue portal faces up, the orange faces down. All velocities are signed so that up is positive, and all velocities are along the vertical axis. What is the final velocity of the block, v_f?

I say that the answer is given by the equation v_i - v_o = v_f - v_b. Notice that this equation is between velocity differences, so it is invariant to Galilean transformations. It should be clear from inspection that the equation I give implies answer B above, as it is the case where v_i = 0 = v_b .

It is easy to demonstrate that the alternative corresponding to A above, namely v_i = v_f, leads to contradictions--for example, particles can go into an orange portal, but exit the blue portal moving slower than the blue portal is moving, which means it doesn't exit at all.[/spoiler][/spoiler]

>> No.6451738

>>6451694
>>6451694
Well, part of your reasoning is muddled by trying to include gravity, friction, the normal force of the platform, etc. It's best to work this out the way a physicist would:

Consider a block of mass M in zero-g, moving at an initial velocity <span class="math">v_i[/spoiler] from the point of view of an external observer. An orange portal approaches at velocity <span class="math"> v_o [/spoiler] and collides with the block. The blue portal is moving at velocity <span class="math"> v_b [/spoiler]. The blue portal faces up, the orange faces down. All velocities are signed so that up is positive, and all velocities are along the vertical axis. What is the final velocity of the block, <span class="math">v_f[/spoiler]?

I say that the answer is given by the equation <span class="math">v_i - v_o = v_f - v_b[/spoiler]. Notice that this equation is between velocity differences, so it is invariant to Galilean transformations. It should be clear from inspection that the equation I give implies answer B above, as it is the case where <span class="math">v_i = 0 = v_b [/spoiler].

It is easy to demonstrate that the alternative corresponding to A above, namely <span class="math">v_i = v_f[/spoiler], leads to contradictions--for example, particles can go into an orange portal, but exit the blue portal moving slower than the blue portal is moving, which means it doesn't exit at all.

>> No.6451774

Think about it from the portal's perspective rather than the cube.
Whether the cube is moving from it's own frame of reference is irrelevant as from the frame of reference of the blue portal the cube is moving towards it.

>> No.6451802

>>6451774
Also got a pretty crap diagram to help with the idea.
On the blue side of the portal, the portal isn't moving, the momentum of the other portal is irrelevant. So the cube will maintain its velocity relative to the orange portal as it exits the blue one.

>> No.6451807
File: 28 KB, 1207x737, Portal Problem.png [View same] [iqdb] [saucenao] [google]
6451807

>>6451802
I say that and then forget the diagram...

>> No.6451809

A. It's made clear in the games over and over again that only the speed of the entering object is relevant.

"Speedy thing goes in, speedy thing comes out"

>> No.6451816

>>6451809
Exactly, and the speed of the cube relative to the orange portal is conserved.
See:
>>6451774
>>6451802

>> No.6451833

>>6451738
I think you're making a false assumption, starting with violating the wording from the game.

If you want to assert that the portal functions differently than the canon from the game which spawned the concept, then you'll have to describe how the matter is translocated in space to assert that its velocity is changed (i.e., invent the portal). You'll also have to justify your portal concept to the behavior of the portal in game.

For all we know, the matter in the cube is removed entirely from the universe as it passes through the portal and through whatever interdimensional rifting which takes place to bring it back in, changes in direction are nullified, resulting in a zero net change of momentum.

None of these questions are answered, or I think answerable with conventional physics (but I'm totally not a physicist).

Either way, I don't think you can throw out something that was in the game, right along with other things that were also there, like gravity and friction...

>> No.6451867

>>6451833

But that explanation doesn't change anything from the game.

>> No.6451868

>>6451809
>that only the speed of the entering object is relevant.

Yes, and the block has high speed entering the orange portal, therefore the answer is B.

There are a dozen very clear explanations ITT for why it can only be B.

>> No.6451870

>>6451816
With that kind of logic, if the blue portal was moving downwards, the same thing would happen. And if it was moving upwards, the cube would fail to exit at all. It's not symmetrical.

>> No.6451872

>>6451870
It doesn't matter. Only the speed of the cube is important. There's only one rule.Seriously play the games.

This isn't even up to discussion.

>> No.6451873

>>6451870
Oops. Meant to respond to >>6451809

>> No.6451879

>>6451870
No it wouldn't because the speed of the portals are irrelevant.

>> No.6451884

>>6451833
I pointed out that the wording from the game was from GLaDOS, who is unreliable. Also, since all portals in Portal 1 were stationary, GLaDOS's statement was true (for magnitude, not direction), but the same statement would be true for my theory.

In Portal 2, there are moving portals, but by careful design, no object ends up passing through them (only lasers). So we don't have any experimental data on what happens when an object moves through portals that are in relative motion. We can't even get any data from the game, since it turns out moving portals were not properly implemented and just act like walls. Nonetheless, we can ask the question: "If an object did pass through a moving portal, and the laws of portals were self-consistent and simple, and the laws deviated as little as possible from the laws of physics as we know them, what would we expect to see?"

What we have are two theories which both agree with everything that is said in the game, and with all the data we have for stationary portals, but which disagree in their predictions for moving portals. One of those theories is not self-consistent: Theory A predicts impossible things like an object entering one portal but failing to exit the other. Theory B, on the other hand, is self-consistent. There *could* be a more complicated theory C that is also self-consistent and consistent with the evidence we already have, but none has been proposed, and any such theory would probably be needlessly complicated, which counts strongly against the theory's likelihood.

>> No.6451896

>>6451879
That's what I'm saying. It can't be A and have the speed of the portals be irrelevant. It's relevant in both options. You can't ignore it without being able to do weird shit like make the cube disappear completely.

>> No.6452871

>>6451809

And since the cube is speeding towards the orange portal as it enters, it will be speeding away from the blue portal when it exits.