• aerowave@feddit.uk
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    1 year ago

    Speedy thing goes in, speedy thing comes out

    E: I was just quoting GladOS… Not really thinking about the actual physics!

    • Kaosmace@lemm.ee
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      1 year ago

      Yeah but the thing isn’t moving the portal is, and the energy has to come from somewhere if the portal makes the thing go fast.

      • Duamerthrax@lemmy.ml
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        1 year ago

        The energy would come from the trolley. The people would launch out at approximately the same speed as the trolley interacts with them and the trolley would slow down in response to how much kinetic energy was transferred to the people.

  • SecretPancake@feddit.de
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    1 year ago

    I don’t think portals carry the momentum with them. It’s as if the train is a moving tunnel. So A.

  • blurr11@programming.dev
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    1 year ago

    I think it’s A because I assume a portal stitches two points in space to each other.

    So if I have a surface A and B with a portal ‘]’ in the middle A0 A1 ] A2 A3. B0 B1 [ B2 B3

    A portal creates a new surface

    A0 A1 ][ B2 B3

    And if you move the portal the new surface changes.

    A0 A1 A2 ][ B3

    Speed is distance over time. When a portal moves the object that passed through the portal stays stationary. Let’s say I am standing on B2. When the portal advances I find myself standing on A2 , have i moved? No the environment has changed but i am still in the same relative position with respect to the portal surface. No distance travelled so no speed.

    • Amol@feddit.de
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      1 year ago

      I say its B, because if we jump in a portal we fly out of the other one. Now the difference is here the portal is moving and not the person, but in physics we are only interested in the motion of two bodys relative to each other. If you are standing on the train you would see the portal as stationary and the people coming towards it. Because the object/person enters the portal with speed it also comes out with the same speed.

      • Lizardking27@lemmy.world
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        1 year ago

        If you jump into a portal, YOU have momentum, these people are stationary and therefore have no momentum, the answer is A.

        • Amol@feddit.de
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          1 year ago

          There is no momentum without saying relative to what. A train is moving relative to the people not on the train. The earth is moving relative to the sun. But if you are on earth the sun is moving and you are stationary and your viewpoint is not wrong! The reason is, that there is no underlying space we are moving relative to. Maybe this helps: Imagine a train in a train. Driving with the same speed but in the opposite direction. Now from the outside the inner train is not moving at all, but the outer train is. From the inside the inner train is moving and the world around them is. If there is now a portal inside the outer train and the inside train is passing through. What happens. Nothing because the inside train is not moving or it shoots out because it is moving?