If the door is moving 1 meter per second, you are relatively moving 1 m/s towards the door even if you are stationary on the ground. You pass and, although you are still stationary to the ground, you are still moving 1 m/s in the same direction relative to the door. The door is the frame of reference, not the ground.

[–] Kyoyeou@slrpnk.net 2 points 1 year ago (1 children)

But that would signify there is an impact? And that you are crashing at 1m/s, if you don't enter in contact? If I'm in my house, I am not moving at 130km/h from the highway near my house?

[–] Rivalarrival@lemmy.today 1 points 1 year ago

If you are looking at someone through the portal, they will appear to be standing on a parade float. They are standing still on a surface, but that surface is coming at you.

You won't feel any change in momentum as the portal passes around you, but the ground will be suddenly moving under you.

[–] H2207@lemmy.world 1 points 1 year ago* (last edited 1 year ago)

Yes but relative to you the door is moving away and you're stationary. In this example of the portal coming towards you, therefore upon paasing through the other side of the frame, the other portal, is moving away from you.

In this diagram, it's assumed that the person is the frame of reference, therefore I believe A to be the correct outcome.