this post was submitted on 18 Aug 2023
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[–] [email protected] 14 points 1 year ago (4 children)

B

Lets say the train is moving with 10 meters per second. That means that the people will enter the portal with 10 meters per second. Therefore, they will leave the other portal with, you guessed it, 10 meters per second. Henceforth, they will be traveling with 10 meters per second after leaving the portal. 10 meters per second.

[–] [email protected] 8 points 1 year ago

How many meters per second was that again?

[–] [email protected] 5 points 1 year ago (1 children)

If the other portal is on back of the train, they they will stay at rest(might be displaced to back at lengthOfTheTrain distance

[–] Carnelian 4 points 1 year ago

Like that episode of myth busters where they fired a canon backwards out of a moving vehicle

[–] [email protected] 3 points 1 year ago (2 children)

Where will the energy that accelerates the people come from?

[–] [email protected] 4 points 1 year ago (2 children)

The train.

As the object enters the first portal then the inertia of the far end of the object that is forced to pass through will need to be accelerated in the space outside the second portal to pass through, acceleration which is induced by being pushed by the other end of the object still outside the first portal.

In other words, pushing a portal onto an object pushes that object with half the speed of the portal. This will likely require energy put into the portal itself to maintain it, which needs to come from the train.

[–] [email protected] 1 points 1 year ago

That was an idea I'd floated above as well.

[–] [email protected] 0 points 1 year ago (1 children)

The train never touches the people.

The portal touches them first, moving where the people are.

[–] [email protected] 2 points 1 year ago

The portal is moved by the train

[–] dmmeyournudes 0 points 1 year ago (1 children)

The hole in space between the portals.

[–] [email protected] 1 points 1 year ago (1 children)

That hole has momentum? I'm not even sure it exists since by definition a portal is two points without intervening space.

[–] dmmeyournudes 1 points 1 year ago (1 children)

It takes energy to maintain the portal, that is significantly less than it takes to move the people.

[–] [email protected] 1 points 1 year ago (1 children)

Does it? In the games portals last indefinitely with no external energy source. It's an intriguing idea though because it would explain why portals collapse if the surface they're on moves. Any matter that goes through the portal would pull energy from it and cause it to collapse. Matter that goes through a portal that's standing still, otoh, rather famously experiences no change in momentum and therefore does not pull any energy from the portal. So the portal is stable as long as it stands still.

[–] dmmeyournudes 1 points 1 year ago* (last edited 1 year ago) (1 children)

Were talking about a quantum level of energy. Wormholes are not proven to exist but if you were to calculate the energy it takes to travel X distance, the amount of distance you save by using the wormhole has been generated by simply traveling through it, and can even mean you have "generated" energy if he amount saved us greater than the amount spent overall.

[–] [email protected] 1 points 1 year ago

That honestly sounds like an accounting trick to preserve newtons laws than an actual measure of energy in. Though I suppose it would be an answer to the problem of a water wheel between two portals

[–] [email protected] 0 points 1 year ago

The would be moving at 10 meters per second in regards to the train that didn't touch them, the same as the were before the train got close enough to touch them.

Think of it the other way. If the went into the stable portal and came out I'm from of a moving portal, what would happen?

The portal would move forward and swallow them up and spit them back out the way they came in.

They would not have accelerated in the process. They wouldn't fly out the portal they just walked in at the speed of the train. The train didn't touch them so it can't transmit any of its momentum to them.