its B

No its A

>>384828075
cant we just test this on the game itself

>>384828146
pointless, engine not sophisticated enough

>>384827328
>You have to pick a reference point and stick to it.
absolute frame of reference does not exist.
there are simultaneously two valid frames of reference in this problem

>>384828146
In the game the orange portal just stops when it touches the cube
In gmod people were able to replicate both results, don't ask me for webms

File: really makes you think.png (21KB, 634x582px) Image search: [Google]

21KB, 634x582px

So what is it gonna be here? Also please provide the answer to OP's question as well
For me it's A + A
OP's question: B

>>384828830
uh... yours is A
ops is B

i dont get how your B could be possible, how can you enter at 10 ms if youre only moving 1ms towards the entrance?

File: portals.png (22KB, 993x681px) Image search: [Google]

22KB, 993x681px

You should be able to solve this.

SPEEDY THING GOES IN
SPEEDY THING COMES OUT

Why is it that a board that complains so much about remakes and rehashes reposts the same threads every single day?

>>384829378
its fun

i'd have a general

so who actually thinks its A?
im not all argued out yet

it's A, the object going through the portal keeps its momentum. No momentum in, no momentum out

>>384829146
There are two questions in the picture
I made it mostly as a counter point to speedy thing goes in, speedy thing goes out
If it was true, then the bar would exit at the same 10 m/s as it was travelling at before entering the portal, but it would have to enter at the same speed (B + B) or basically disintegrate which is A + B.

>>384829853
where does the momentum from the portal go?
you have one thing moving prior to the box entering the portal
and zero objects moving after the box exits the portal
how can the box even exit the portal without momentum?

>>384829893
Or wait, I fucked up with my own explanation
A+B is entering at 1 m/s and then shooting out at 10 m/s

>>384829893
uh
speedy thing goes in speedy thing goes out is you enter at 1 ms you exit at one 1 ms
i dont get what youre saying

>>384830127
okay this is about absolute reference points vs relative ones
cause absolute parts of your example are breaking my brain

>>384830131
It's about point of reference
In op's question if point of reference is orange portal then the cube enters at high speed and comes out either at zero speed or the portal's speed
People that argue about momentum say that cube will preserve its speed at this point which is zero
So it should preserve its speed in my picture if the point of reference is the blue portal in that case which is 10 m/s

>>384830498
youre not getting the ops picture

its about absolute vs relative frames of reference
A is absolute frame of reference
B is relative frame of reference

A has one frame of reference in which box is not moving

B has two frames of reference
prior to entering and after the exit
in B box is moving and stationary at the same time

>>384829965
portal doesn't have momentum, for all purposes its a hole more or less

>>384830990
it is moving, it has momentum

File: 123.png (19KB, 1069x518px) Image search: [Google]

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if A would be correct, after passing a hulahoop you would get sucked to the exit and continue moving with it

https://www.youtube.com/watch?v=b4xmHNgiYtA

>>384830685
I actually do get OP's picture
If there is one point of reference than the bar should exit at 10 m/s
If there are two points of reference then the bar is moving at 10 m/s prior to exiting the portal and at 1 m/s relative to the orange portal and after exiting from it

>>384831353
isnt that what i said

>>384831353
Well yes, I just want to show what would happen if the correct answer to OP's question is A.
The bar will either be sucked into the blue portal at 10 m/s or enter at 1 m/s and then shoot out at 10 m/s.

>>384831130
no takers?

File: portal_answer.png (286KB, 1712x1752px) Image search: [Google]

286KB, 1712x1752px

Valve developer says it's pretty much B in his opinion.

http://www.strawpoll.me/13504425

>>384832531
>No. A. 15 votes
how can you believe this when it directly contradicts itself?
i dont understaaaaand

>>384828075
box has no momentum when entering portal,
so A

>>384832823
okay let me try to prove you wrong
you are talking about this as if the world has an absolute frame of reference, yes?
the box is not moving but the portal is moving so the box stays still, is what youre thinking
right?

>>384832920
yes

>>384832994
when you are in a moving car
and you throw a ball up
it moves up and then down
instead of flying back
why?

>>384828075
Both and neither; it's a paradox because the box is both moving and not moving at he same time.

>>384833058
its not a paradox, the box is moving relative to the first frame of reference and is stationary relative to the second frame of reference
a portal just makes it possible for two frames of reference to exist in the same place with the same objects

>>384833057
because ball has forward momentum equal to car

>>384833057
because that's real physics

portal is vidya physics

>>384833168
but doesn't that imply relative reference points?
the ball is not moving relative to you, or the car
but it is moving relative to the road

if there are two objects in space, how does one determine which object is moving and which is stationary?

>>384833368
your right it's relative. you measure it at a point of reference. but you can assume in this photo that they will have similar conditions between the two points connected by the portal.
i.e. if one end of the portal is in the car, the other is too.

File: themoreyouknow.gif (394KB, 305x185px) Image search: [Google]

394KB, 305x185px

>>384829284
>SPEEDY THING GOES IN
>SPEEDY THING COMES OUT

Define "speedy thing goes in". In what frame of reference must it be "speedy"?

One common argument in favor of Scenario B is that the question of whether the cube is "speedy", as it goes in or goes out, must be answered in the appropriate portal's frame of reference. In the orange portal's frame of reference, the cube is indeed speedy as it goes in. Therefore, the argument goes, the cube should be speedy in the blue portal's frame of reference as it exits. In other words: Speedy thing goes in (according to the orange portal's reference frame), speedy thing comes out (according to the blue portal's reference frame). The problem is that, in this particular problem, the portals are in two different frames of reference. Such a change in reference frame is typically not permitted when figuring out a physics problem.

The common argument in favor of Scenario A takes the normal approach to a physics problem. It says that we should pick one reference frame — that of the ground — and stick with it. In this frame of reference, the cube is not speedy when it enters and therefore should not be speedy as it exits. But now we have another problem. How does a cube come out of a stationary portal without moving with respect to that portal? The cube cannot be stationary throughout the entire experiment, and here's why: It must, at least, move a distance equal to its own length, in order to come out of the blue portal, which remains stationary in our chosen reference frame. The cube could not end up on the outside of the blue portal if it had not moved through that opening.

This brings us to another common argument in favor of Scenario B, which is simply that the cube must move with respect to the blue portal as it comes out of the blue portal. And, if the cube is moving during this transition, there's no obvious reason that it should abruptly stop moving once the transition is complete.

>>384829965
the portal has no momentum, the portal has no mass, it's not there

imagine how it looks in the last few picoseconds of it happening, when the platforms are really close but not fully connected

the box is half-way through the portal, and obviously the other half appears on the other portal. now still hasn't touched the moving platform, because it went right through the portal.

after the moving platform and the lower platform connect, what is relative on the other side of the outgoing portal is the floor of the lower platform. that platform wasn't moving so why would it suddenly launch the box?

>>384831041
The portal isn't moving, the machine is. The portal is literally just a hole in the universe from one point to another. They don't move or have momentum

>>384833717
>i.e. if one end of the portal is in the car, the other is too.
but that is exactly what is not the case
as the entrance and exit are moving in different directions and different velocities relative to each other
it's as if there are two cars moving in different directions, while being the one and the same car, which is where the problem of the cubes speed comes out

prior to entering the portal two things are stationary and one this is moving, the portal
after the exiting in scenario A, all three things have abruptly stopped for some reason, while scenario B has consistency of a single object being still in motion at the same speed, but it is now the box

>>384834096
>The portal is literally just a hole in the universe from one point to another.
it is the hole to the universe, that moves with the orange portal, as the orange portal is being moved towards the box
effectively meaning that the perspective is this: a box and a universe are moving towards each other with certain speed

>>384833920
because the universe is moving towards the box, and it doesn't matter which one is moving, it only matters that they are moving relative to each other
you are describing an absolute reference point

If you have any doubt about /v/'s scientific illiteracy, here's a list of some of the claims that were made in today's earlier Portal threads:

• There is only one true reference frame.
• Motion is not relative.
• The idea of motion being relative is the same as the theory of special relativity.
• Momentum is not relative.
• Momentum is not a vector.
• The law of conservation of momentum means that only the magnitude of each body's momentum must be conserved.
• Portals conserve momentum, just because a video game character said so, despite the fact that two portals can change the direction of a single moving object while themselves remaining stationary, thus changing the total momentum of the system.
• Kinetic energy is not relative.
• Potential energy doesn't count.
• Portals conserve energy despite the fact that you can use two portals and a water wheel to create an infinite energy machine.

People on this board actually believe these things. Most of them think the answer is A.

>>384834196
The portal isn't moving the universe. It isn't moving anything. It's literally just like putting a hole in a piece of paper.

>>384833154
You just said relative to the second frame, which quite literally means what they just said. So yes, it is a paradox.
Its moving, and not at the same time, depending on frame of reference.

>>384829284
Relative to the portal (which is the only thing that fucking matters in this problem) the cube is speedy. The portal is moving which means the cube enters the portal at the portals speed, and comes out the second portal at the first portal's speed.

>>384834530
You listed all the reasons why its A, and yet you make it sound like you think its B?
Odd.
>>384834694
You forgot the portal is no longer speedy once it collides with the platform holding the cube, which also means the cube is also stationary in comparison to the portal after the portal comes to a stop, due to collision.

>>384834115
I guess I understand why this is a paradox
If you consider the portal to apply momentum to the universe on the other end of the portal I could see where your coming from, but that's not how I consider portals. I consider portals sorta like a forth spacial dimension. They don't contain the universe and there momentum is independent from the three spacial dimensions.

>>384834602
a hole in a piece of paper has its entrance and exit move at the same speed and direction
a portal with its exit stationary, means that the entrance portal effectively moves the whole universe with it, as it being moved towards the box

if you were thinking about an example of folding space with paper and a pencil, my explanation still makes sense and should be easily visualized by you

>>384834623
but that is why its not a paradox
the box is stationary in the blue frame of reference while moving in the orange frame of reference
the only problem with this is that portals are impossible, and would require an infinite amount of energy, same as trying to move an entire universe towards a box, trying to move faster than light, or creating pure vacuum

>>384833057
Well according to /v/ when you toss a ball up in the air in a car it should fly back and smash through the window.

>>384834837
>You listed all the reasons why its A
They are all also false, which you would know if you were literate.

>>384834903
>"Its not a paradox, because it can be both things, even though its impossible"
thats what a paradox is...

>>384835030
Im referring to your opinion that the list isnt accurate, aka, you either think they are wrong, or the opposite, which is what I mean by why you are listing your opinions as to why, indirectly.

>>384834837
Because those reasons are incorrect dumbass. They're principles of physics accepted for a long time yet /v/ thinks they're smarter than physicists.

>>384829224
A

>>384835157
see>>384835142
While poorly phrased, I dont mean the list directly is the answer, but that your list indirectly tells us your reasoning.
And yet, with your reasoning, you still get to B.

>>384834854
but its not a paradox


>>384835031
its not cause from both frames of reference it is valid
you just need to think out of the 3d box
box is stationary until the frame of reference changes
but relatively the box is always moving towards the universe and the universe is always moving towards the box

>>384835270
the list only shows the ridiculous lack of understanding of any kind of physics by people in previous threads that believed that the answer was A

>>384829224
Neither

>>384829224
Now THIS is the best way to show the paradox.
As both answers "should" be correct, and "incorrect".

OPs question makes it harder to see, because both portals are stationary in the final answer.

>>384834854
why would it be a paradox if you're looking at it fourth dimensionally?
if anything it only supports that it isn't a paradox

>>384828075
If the platform the cube was sitting on wasn't there it would be B

File: 1495752653747.jpg (59KB, 750x683px) Image search: [Google]

59KB, 750x683px

>b
>Cut hole in paper
>Slam paper on desk over box
>Box flies into space

>>384833839
This. There is no correct answer because the portals themselves already violate physics this we can't apply known physics concepts to it to get a conclusive answer. This it comes down to whatever the game designers decide makes sense for design purposes

>>384835516

>Be unable to solve problem
>Remove the confusing part of the problem to create a completely different problem
>Logic flies into space

>>384835479
how the hell would it show that its a paradox?
A scenario shows that the box is standing still even though it should be moving
while B shows everything being in order according to relative movement

>>384833057
Would a humming bird on a moving plane hit the back of it if it was just hovering?

>>384835297

see

>>384831130

In 1 example its moving in comparison to the portal, but not in the other.
In the 2nd example, its not moving to one portal, but it is to another.

Its both stationary and not stationary in both, which requires it to break a prior rule for either to be true.

>>384835664
Portals are literally just holes. It explains the problem in a way that can be recreated.

>>384835673
Both answers show the same answer....
A is not stationary to the orange portal, only to the blue portal.
In the 2nd, its stationary to the orange portal, but not the blue portal.

So is it stationary or not anon?

>>384835717
>see *my own picture*

>In 1 example its moving in comparison to the portal, but not in the other.
its moving in comparison to both portals in B

>Its both stationary and not stationary in both
its not, it is stationary in B cause the entrance and exit is moving at the same speed, and there are relative reference points

in A it is moving at different speeds if absolute reference point existed, which is retarded

>>384835818
>Portals are literally just holes. It explains the problem in a way that can be recreated.
portals are not just holes, and the problem can not be recreated cause portals are impossible
dragging the problem to your level and removing variables doesn't solve the problem

>>384835840
both are not the same answer
A is stationary relative to the blue portal
B is not stationary relative to any portal, cause the frame of reference changes as the cube passes through the portal

>>384835945
not my picture anon.
>>384836125

>A
Compared to the Blue portal.
Stationary.
Compared to the Orange portal.
Moving.
If you were "living attached to the orange portal, it would look like the cube is moving.

>B
Compared to the Blue portal.
Moving.
Compared to the Orange portal.
Stationary.
If you lived attached to the blue portal, it would look like its moving.

The cube passes through the portal in both examples anon.

When will those threads be nuked on sight?
The picture is wrong anyway, the cube in A should not even move becaue the portal cannot cover completely in the given exemple.

>>384835818
Except with your paper hole, both ends are moving. With the portal one end of the hole is moving and the other is stationary, so relative to the portal, the cube is moving. If you looked through the blue portal, you would see the cube rapidly approaching.

>>384835818

The one interesting aspect of portals is that they connect two distant points in space, i.e., they act like they exist in the same space even though they don't.

The one interesting aspect of this particular portal problem, meanwhile, is that the entrance and exit portals are not in the same frame of reference, i.e., one is moving with respect to the observer's reference frame and the other is not.

You removed both of those aspects from the problem.

>>384836259
im saying that its MY picture
so either im bad at drawing or youre bad at understanding pictures

if were talking about MY picture
in A the portal magically sucks up to the exit even though by all logic it should have been continuing its movement, which implies absolute reference point by the ops picture

in example B, object exits the portal at the same speed it entered the portal, making it consistent, and moving relatively to the portals

in MY picture A has it stationary towards one end of the portal but not the other
and B has it moving relative to both ends of the portal

>>384836267
> the cube in A should not even move becaue the portal cannot cover completely in the given exemple.
what do you mean, havent heard that one yet

>>384835142

This post is a clusterfuck of bad English. I don't even know what you're saying anymore.

Let me just be perfectly clear because you apparently cannot: Each bullet point in the list posted here >>384834530 is a false statement. If you believe those statements, you are scientifically illiterate. That is all.

how is this so hard for people?
A:
box not moving
one portal not moving
one portal moving

WHOOPS NOTHING IS MOVING FOR SOME REASON

B:
one thins is moving
two things not moving

MAKES FUCKING SENSE INNIT