"speedy thing goes in, speedy thing comes out."

So stationary thing goes in, stationary thing comes out.

A, but it would have the average of the two states.

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

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.

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.

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.

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.

Since nobody seemingly posted link to this absolute ... Idk, gold? It's about actually simulating space(-time?) with portals: https://youtube.com/@optozorax_en I see offspec's comment is mentioning the guy, yeah. Tldr answer is complicated.

...

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

This is Einstein's elevator thought experiment but with portals.

B

Also, if the cube has to emerge out of the blue portal top first it has momentum moving out of the blue portal, as seen by the blue portals frame of reference. It can't emerge with zero momentum or it wouldn't move relative to the blue reference frame.

But in portals physics the answer is A.

The object's momentum is preserved. Movement of the entrance portal does nothing. Think of it like stepping though a door, except you're Buster Keaton and the door hole is falling on you.

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

B

The cube gets sucked into the portal with the same force the platform in A is getting sucked upwards.

The question is: Is it the velocity of the object relative to the portal that matters or the velocity of the object in some other frame of reference?

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.

Speedy thing goes in, speedy thing comes out.

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

Ragebait aside the answer is B.

If you had a table with a cylinder, with a ping pong ball in it, and a circular weight dropped around the top of the cylinder that hits the table, the ping pong ball will bounce due to the forces of the weight hitting the table. Enough energy would be transferred through the impact, that would cause the ball to seemingly jump up in the cylinder.

Physics are weird.

A, momentum is in the portal, not the cube