Which is it Lemmy?

Comments

• Peffse@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  Image

  source

  • ThatWeirdGuy1001@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Stop stealing all my upvotes

    source

    • athatet@lemmy.zip ⁨2⁩ ⁨weeks⁩ ago

      You asked a question and they gave an answer. Why wouldn’t they get the upvotes?

      source

      • -> View More Comments
  • HopeOfTheGunblade@lemmy.blahaj.zone ⁨2⁩ ⁨weeks⁩ ago

    Perfectly understood the assignment, 10/10, no notes.

    source
  • Fedizen@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    There’d be no cube but yes

    source

    • victorz@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      In the first moment of exit, it might look like this though

      source
    • ButteredBread@sh.itjust.works ⁨2⁩ ⁨weeks⁩ ago

      why

      source
• TotallynotJessica@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  You can’t place a portal on a moving surface in either game, so neither.

  source

  • lime@feddit.nu ⁨2⁩ ⁨weeks⁩ ago

    you can in one specific spot in portal 2!

    source

    • Sonotsugipaa@lemmy.dbzer0.com ⁨2⁩ ⁨weeks⁩ ago

      Two, if you count… the big one at the end

      source

      • -> View More Comments
    • Mika@piefed.ca ⁨2⁩ ⁨weeks⁩ ago

      So now we just need to build this test in there and we are set

      source
  • ThatWeirdGuy1001@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    So the cube is just smashed?

    It’s a practical answer which is slightly upsetting because I wanted more discourse.

    source

    • kkj@lemmy.dbzer0.com ⁨2⁩ ⁨weeks⁩ ago

      No, cubes cannot be destroyed by crushing. The portal disappears when the surface moves and then the cube stops the surface’s descent.

      source
  • viertesauge@feddit.org ⁨2⁩ ⁨weeks⁩ ago

    what about the portal on the moon?

    source

    • luthis@lemmy.nz ⁨2⁩ ⁨weeks⁩ ago

      Well, everything is moving or not moving, relatively

      source
    • alsimoneau@lemmy.ca ⁨2⁩ ⁨weeks⁩ ago

      It’s unstable and will dissipate on its own when the relative displacement between them will be too great.

      source
  • gnufuu@lemmy.ca ⁨2⁩ ⁨weeks⁩ ago

    Skill issue

    source
  • rethnor@lemmy.zip ⁨2⁩ ⁨weeks⁩ ago

    You’d make a horrible scientist.

    source

    • TotallynotJessica@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      It said ragebait answers only ¯\_(ツ)_/¯

      If it is a question of real life physics, then B would be correct

      source

      • -> View More Comments
    • kkj@lemmy.dbzer0.com ⁨2⁩ ⁨weeks⁩ ago

      Scientists know when to use existing knowledge.

      source
• surewhynotlem@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  This was answered decades ago

  Image

  source

  • I_Has_A_Hat@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    In that situation both portals (the inside and the outside window frame) have equal, but opposite velocities and therefore cancel out any momentum from the person.

    When dealing with OP’s scenario, only one portal is moving.

    source
  • zerodawn@leaf.dance ⁨2⁩ ⁨weeks⁩ ago

    wikipedia.org/wiki/Steamboat_Bill,_Jr.

    Nearly a century ago. Fun fact, this movie inspired Steamboat Willie, the very first appearance of Micky Mouse.

    source
  • min@lemmy.sdf.org ⁨2⁩ ⁨weeks⁩ ago

    The problem with this analogy is that both sides of the window are at the same point in space so there is no pressure differential. What if the blue portal was at the bottom of the Mariana’s Trench? What force displaces the water to place the cube on the other side?

    source

    • surewhynotlem@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      It wouldn’t. Same as if the other side of the portal was a brick wall. It wouldn’t go through or would be smooshed by whatever force is driving the portal.

      source

      • -> View More Comments
• Sonotsugipaa@lemmy.dbzer0.com ⁨2⁩ ⁨weeks⁩ ago

  According to a gravitationally accurate simulation a guy did for Youtube, the correct answer is_

  … ah, ragebait answers only. Well, mission accomplished, probably >:3

  source

  • Equinox1289@sh.itjust.works ⁨2⁩ ⁨weeks⁩ ago

    For anyone who doesn’t know, Optozorax on YouTube has made a finite element analysis simulation of gravity ontop of his portal simulation so we can get an answer to the question. The answer is both. Both happen depending on how fast the portal is moving.

    source
  • ButteredBread@sh.itjust.works ⁨2⁩ ⁨weeks⁩ ago

    wait is that the alt text? My client doesn’t evem display alt text… I think.

    source

    • Sonotsugipaa@lemmy.dbzer0.com ⁨2⁩ ⁨weeks⁩ ago

      I’m not sure if it’s the alt text or simply the post’s body, but it reads “Ragebait answers only”

      source
• Tar_alcaran@sh.itjust.works ⁨2⁩ ⁨weeks⁩ ago

  Option B. Portals already break a couple of laws of physics and can reverse entropy, but I like to think you should look at the speed of an object relative to the portal.

  source

  • toiletobserver@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Speedy thing go in, speedy thing come out. Clearly explained in game.

    source

    • rethnor@lemmy.zip ⁨2⁩ ⁨weeks⁩ ago

      But I’m this case the cube has no speed, so it wouldn’t just suddenly start moving.

      source

      • -> View More Comments
  • min@lemmy.sdf.org ⁨2⁩ ⁨weeks⁩ ago

    What if the blue portal is at the bottom of the Marianas Trench?

    source
• Olgratin_Magmatoe@slrpnk.net ⁨2⁩ ⁨weeks⁩ ago

  Niether. Moving surfaces break portals instantaneously.

  source

  • brockhold@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Portal 2 has moving surfaces, with the cop-out that it’s accelerating surfaces that cause the portal to break.

    spoiler

    No matter that you literally put a portal on a different planet…

    source

    • ChaoticNeutralCzech@feddit.org ⁨2⁩ ⁨weeks⁩ ago

      Portal 2 only has laterally moving surfaces, that inherently don’t cause things to enter the portal.

      source
• Tigeroovy@lemmy.ca ⁨2⁩ ⁨weeks⁩ ago

  Portals don’t stay on moving platforms.

  But if they did, it would be A as the cube itself has no momentum.

  source

  • Apytele@sh.itjust.works ⁨2⁩ ⁨weeks⁩ ago

    WHAT DID YOU NOT UNDERSTAND ABOUT RAGEBAIT. ANSWERS. ONLY.

    source

    • buddascrayon@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      … Uh

      u mad?

      source

      • -> View More Comments
    • Rolive@discuss.tchncs.de ⁨2⁩ ⁨weeks⁩ ago

      It seemed to work.

      source
  • MimicJar@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Except that one time when you use it to cut the neurotoxin pipes.

    source

    • dunyol@lemmy.blahaj.zone ⁨2⁩ ⁨weeks⁩ ago

      Yeah but those are moving from side to side. To my recollection, you never see a portal in a wall that’s moving in a direction that’s perpendicular to the plane it’s in.

      source
  • Flames5123@sh.itjust.works ⁨2⁩ ⁨weeks⁩ ago

    The speed of one thing is the same speed of the other if you change the reference point. So the cube has momentum but the moving platform does not. It’s more about having a velocity in respect to the portal it’s going in or coming out of or an average of both. Like when you jump into a portal, you come out faster on the other side. Now what if that out portal was traveling at the same rate? Would you be traveling just outside the portal or double speed (in relation to the ground and static objects in the same room)?

    source
• UnderpantsWeevil@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  Ragebait answers only

  I’m giving so many people Fs on this assignment because you failed to read all the instructions.

  The correct answer is B due to the graphical conservation of speed lines.

  source

  • ThatWeirdGuy1001@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    I did it deliberately.

    Lemmy reads more than most but people aren’t good at reading

    source
  • iocase@lemmy.zip ⁨2⁩ ⁨weeks⁩ ago

    I think any answer is a ragebait answer because nobody here understands physics

    source

    • UnderpantsWeevil@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      That’s definitely a ragebait answer

      source

      • -> View More Comments
  • ericwdhs@discuss.online ⁨2⁩ ⁨weeks⁩ ago

    Trick question. Fun answers are not ragebait. Serious answers (correct or incorrect) are ragebait. You get an F.

    source
• chefdano3@lemmy.zip ⁨2⁩ ⁨weeks⁩ ago

  “speedy thing goes in, speedy thing comes out.”

  So stationary thing goes in, stationary thing comes out.

  source

  • weps@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Speedy or stationary relative to what?

    source

    • uniquethrowagay@feddit.org ⁨2⁩ ⁨weeks⁩ ago

      To the portal if course. That’s why it comes out speedy at the other end.

      source

      • -> View More Comments
  • ChaoticNeutralCzech@feddit.org ⁨2⁩ ⁨weeks⁩ ago

    > stationary
    > comes

    Choose one. There is no “plop”, all of the cube has to emerge on the blue portal’s plane

    source
• Simulation6@sopuli.xyz ⁨2⁩ ⁨weeks⁩ ago

  If the downward moving portal hits the platform and there is some elastic rebound, then the object will bounce outward slightly.

  Rage bait answer: Portals can’t exist, it is from a child’s game.

  source

  • chuckleslord@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Better rage bait answer: portals can’t move relative to each other. If they do, the one that is moving ‘pops’ and disappears from the surface. So this scenario is impossible inside the parameters of the game, so it’s not worth thinking about.

    (The devs realized a lot of stuff could get horribly broken if portals could move, so they can’t move)

    source

    • Demivan@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      Except that they can move in that one level with gas and lazers )

      source

      • -> View More Comments
    • ericwdhs@discuss.online ⁨2⁩ ⁨weeks⁩ ago

      Even stationary portals break conservation of energy unless there’s some unseen location changing energy to compensate, but yes, it gets more complicated with relative movement. In lore though, it is established that portals can move relative to each other at least with enough distance when you ::: spoiler spoiler shoot one portal to the moon :::.

      source
• mirshafie@europe.pub ⁨2⁩ ⁨weeks⁩ ago

  B.

  Momentum/velocity is not an intrinsic property of an object, it is a relative property between two objects in a frame of reference.

  Behind the yellow portal is the part of the universe where the blue portal is. The yellow portal, and therefore the space where the blue portal is, has momentum relative to the cube.

  Put yourself in the frame of reference of the cube. You see the yellow portal come toward you. Imagine there are objects on the other side of that portal. You see those objects rush toward you through the portal. Why would the objects just stop dead when you came through the portal? (If they did just stop, it would be as though you hit a wall, and you wouldn’t actually go through the portal at all.)

  source

  • kryptonianCodeMonkey@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Also consider the duration of the time that the portal is passing over the cube. It is moving at speed, the entire way through the portal and out the other side and then it just stops dead immediately once through? That would hardly be a conservation of momentum anyway from any frame of reference and does not make any intuitive sense.

    source

    • mirshafie@europe.pub ⁨2⁩ ⁨weeks⁩ ago

      This exactly. Consider an object that isn’t a point mass (like the cube) going through. As the first atoms go through, and thry just stopped relative to the portal boundary, that would suggest the next layer of atoms need to exert force on the first layer to push through. But portals in the game Portal do not have any resistance to objects passing through them.

      source
• Ibex@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  The object going into the portal has no momentum so it would be A.

  source

  • flying_sheep@lemmy.ml ⁨2⁩ ⁨weeks⁩ ago

    No momentum in relation to what? Momentum doesn’t exist in isolation.

    source

    • philipp_@discuss.tchncs.de ⁨2⁩ ⁨weeks⁩ ago

      Momentum relatively to the source game engine grid.

      source
    • Nalivai@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

      To the space outside of the blue portal. Moving the orange portal doesn’t drag the whole surroundings, so assuming both places are on the same planet, the momentum of the box in relations to both places is the same

      source

      • -> View More Comments
• crapwittyname@feddit.uk ⁨2⁩ ⁨weeks⁩ ago

  Momentum is conserved when passing through a portal. In the reference frame of the out portal, the object has no momentum, so it plops out.

  source
• codexarcanum@lemmy.dbzer0.com ⁨2⁩ ⁨weeks⁩ ago

  Portals aren’t real and so work however you want them to, but people rarely consistently apply their models.

  I’d say A given how they work in the games though. Only the object’s momentum is conserved. The portal doesn’t transfer momentum. There may be a slight breeze coming out of the blue end as the column of air in front of the portal-plate is pushed in, but the cube is just going to flop out.

  source
• Kolanaki@pawb.social ⁨2⁩ ⁨weeks⁩ ago

  The object’s momentum is preserved. Movement of the entrance portal does nothing.

  source

  • ThatWeirdGuy1001@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    I brought this up on another comment that’s for some reason now deleted but, if the universe moves around you, would you not perceive it as modernity?

    Image

    source

    • Derpenheim@lemmy.zip ⁨2⁩ ⁨weeks⁩ ago

      There is no such thing as an absolute inertial frame of reference. If you are in free fall on earth, you would experience the same sensation as being in space. The only things that would tell you otherwise are the air resistance hitting you and what you can see.

      So no, you would not be able to tell the universe is moving around you unless something else in the universe hit you.

      source

      • -> View More Comments
  • tomi000@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

    Whats the difference between an object moving and everything else moving? For an observer on the sun every one of us has huge momentum which would be preserved when entering a portal. Momentum is always relative to some frame of reference. Momentum ‘toward’ the portal would be conserved and mirrored through the other portal.

    source

    • Kolanaki@pawb.social ⁨2⁩ ⁨weeks⁩ ago

      The difference in this case is that the object has 0 momentum and the portal doesn’t impart its momentum to the cube because you can’t collide with the portal.

      source

      • -> View More Comments
  • berber@feddit.org ⁨2⁩ ⁨weeks⁩ ago

    well, in my opinion it is a bit of a paradox. i think you are partially correct.

    your door analogy may be right from the perspective of the platform on which the cube is. however, one flaw is that the whole space is moving, not just the door. as soon as the cube enters that door, it will be inside that space, and if you consider the cube part of it, moving that space “downward”, then due the cube being held by the platform, you could consider the cube moving “upward” in the space behind the orange portal. if you consider preserving momentum there, then as soon as the apparatus stops moving, the cube should not stop its momentum and move further up in the space.

    or look at it like this: if you are behind the orange portal, meaning you are looking at the blue portal, you will see a cube moving towards you. then as soon as the platform hits the wall of the orange portal, the preserved momentum should make the cube “fly”.

    the change of perspective leads to two different conclusions, therefore i think it is a paradox.

    the problem sort of is that there are two “spacetimes” that are kind of being changed. one could interpret it as both of these effects “pulling” against each other since when the cube has partially passed the portal, one part of the cube is “in one of the spacetimes”, ant the other part in the other. ultimately though, the cube then would actually fly because in the limit (infinitesinally close to when the platform hits the portal wall) the cube is completely on the other side of the portal, so from the view of that spacetime, the cube does get pushed and should fly.

    i don’t even remember if it is possible in the video game for walls with portals that move. a video game would probablt have some kind of “center of mass”, like a single vector of coordinates where describing the position of the object. there is no notion of “partially” being somewhere (except for collision boxes, but i don’t mean that). so also from that view the box would fly. however, in most video games (with or without portals), if a platform moves up and suddenly stops, the object won’t travel further in that direction anyway, especially not ulwards (even sideways usually not).

    source

    • Elgenzay@lemmy.ml ⁨2⁩ ⁨weeks⁩ ago

      As for the portals moving in the game, portals are destroyed if the panel they’re on is moved except for one specific part, where you can put a portal on a panel moving laterally to get a laser to cut the tubes connecting to the neurotoxin tank. That part needed to be explicitly programmed to allow it, and it’s not possible without cheating to physically reach that portal.

      source
  • Master@sh.itjust.works ⁨2⁩ ⁨weeks⁩ ago

    It would move really fast through the portal then slide down from stand still. So yea B is correct.

    source
• bitjunkie@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  Speedy thing did not go in

  source
• luthis@lemmy.nz ⁨2⁩ ⁨weeks⁩ ago

  Speedy thing goes in, speedy thing comes out.

  Cube had no speed going in, therefore no speed going out. The portal speed is irrelevant

  source
• UltraGiGaGigantic@lemmy.ml ⁨2⁩ ⁨weeks⁩ ago

  I choose A because that would mean I could use the portal to fuck myself in the ass easier.

  source
• megopie@lemmy.blahaj.zone ⁨2⁩ ⁨weeks⁩ ago

  The question is, Is it the velocity of the object relative to the portal that matters or the absolute velocity of the object?

  In the later case, we must ask how the portals at different angles don’t send objects flying off at the speed of the milkyway’s travel through the universe.

  The answer that requires the least assumptions and justifications is B.

  source
• Bytemeister@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  If we’re only supposed to do ragebait answers, then anyone who passed 3rd grade science would be able to tell you the answer is obviously B

  If you actually played the game, and paid attention in physics class in highschool, then you would know the answer is clearly A, and everyone who says it is B really needed the simplified explanation from GLaDOS to understand how to play the game.

  source
• ChaoticNeutralCzech@feddit.org ⁨2⁩ ⁨weeks⁩ ago

  www.youtube.com/watch?v=B19nlhbA7-E

  Not providing a link to alternative platforms is my ragebait

  source
• hperrin@lemmy.ca ⁨2⁩ ⁨weeks⁩ ago

  It went through the portal at speed, so it should exit the portal at speed. That’s my take.

  source
• portifornia@piefed.social ⁨2⁩ ⁨weeks⁩ ago

  My take:

  The cube’s mass is x (eg one gram) and its velocity is zero, therefore its momentum (m*v) is zero. Objects in motion tend to stay in motion, while objects at rest (e.g. momentum of zero), tend to stay at rest.

  The thing which is moving, is the portal. At best, the event horizon of it reaches the leading-end then the trailing-end of the cube at the speed the portal is moving over the depth of the cube. If the portal moves faster, that distance is covered faster, and the full cube is entirely on the other end of the other portal faster [than a slower moving portal].

  Since going through the portal is a frictionless and forceless action, the speed at which the portal fully envelops the cube would neither add nor remove momentum upon it. And if the cube did have its own momentum it would be maintained, but since it does not, the cube would not move until another force, like gravity, acted upon it.

  So, A.

  source
• SuDmit@lemmy.blahaj.zone ⁨2⁩ ⁨weeks⁩ ago

  Since nobody seemingly posted this absolute … Idk, gold? youtu.be/1zgBwQVr-wI

  …

  Ah, ragebait answers only. Ugh, worm! Arrrr! I am so angry roar grrrr.

  source
• rob_t_firefly@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  Neither, I’ve already gleefully incinerated that fucking cube before it got to this point.

  source
• MrRandom@lemmy.zip ⁨2⁩ ⁨weeks⁩ ago

  neither, no portal rules were given. Please create an Aperture support ticket.

  source
• Sgt_choke_n_stroke@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  A, momentum is in the portal, not the cube

  source
• myotheraccount@lemmy.world ⁨2⁩ ⁨weeks⁩ ago

  Neither. The cube is not making contact with the portal at all, since the portal is on a stationary block with some speedy lines drawn on it. Speedy lines don’t nake thingy go fast - everyone witb a gel-hairstyle knows that.

  source
• Azrael@reddthat.com ⁨2⁩ ⁨weeks⁩ ago

  It would probably be A because of Newton’s first law of motion.

  source