>>718996880
you're looking at it wrong
What is the B argument? That the velocity X of the portal moving thanks to the piston (also moving at velocity X) is just the inverse (vectorially speaking) of the velocity of the cube on the platform moving towards the portal. So, the cube is going to shoot out of the portal at velocity -X, because that's the vector it originally had due to the "relativity" and "frame of reference" line of thought.
Thing is, in the spaceship analogy, if you think of the spaceship as the portal/piston, this only happens if the ship is actually allowed to pass PAST the portal...
What does happen, instead, if the ship stops dead in its track? What is its velocity from the frame of reference of the cube? What is the cube's velocity from its frame of reference?
I literally can't make it any simpler than this without bringing the two images to a kindergarten class
>>718996307
