Fair point, we can measure that, it would match the speed of the portal falling. It still won't launch the person as it isn't transferred but you can certainly measure the speed of the portal using it.

[–] lauthals@feddit.de 1 points 1 year ago (2 children)

But now, when you have a moving object (my body) we need a force to stop that momentum. Where does that force come from?

[–] Shiki@lemmy.world 0 points 1 year ago (1 children)

The force that's keeping you on the ground from the other portal

[–] lauthals@feddit.de 1 points 1 year ago

That'd be gravity. But the difference is that we are not moving (at least not relative to the ground) before entering the portal, so gravity just keeps us at the bottom.

After entering the portal, we are having a movement to the speed of the entering portal as we already established. So, gravity has yet to work against this motion (which will, of course, eventually keep us on ground again because gravity does its thing. But temporarily, and depending on the actual speed, we might have a bit of air time in this scenario).

I have my doubts, that this will convince you now. However, I gotta say, it was a lot of fun discussing this completely speculative topic with you. Also, I give you, that - while I'm still 100% sure that B is the only sensible solution for this question - you helped me better understand why people might think A is correct.

Have a nice one :)