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Anon develops free, worldwide public transit (sh.itjust.works)
submitted 2 years ago by to c/greentext@lemmy.ml
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[–] 8 points 2 years ago (4 children)

This would be possible if there was a material unaffected by gravity, right?

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  • [+] 27 points 2 years ago* (3 children)
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  • [–] 11 points 2 years ago (2 children)

    If you accelerate the passenegers to the same speed as the train while they board, then you can solve one of those problems. I suggest firing them out of a canon.

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  • [–] 7 points 2 years ago

    Keep the ideas coming guys, this is a great brainstorming session. I think you have solved most of the practical issues. I'll talk to the investors, but I think WE are almost there!

    On a related note, everyone in the R&D department is being terminated.

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  • [–] 4 points 2 years ago* (1 child)

    What if we figure out a way to safely transport people IN something like a missile, self propelled, and can be launched on a schedule. Then we wouldn't need the train at all!

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  • [–] 5 points 2 years ago

    Missiles are super inefficient. You have to overcome gravity while fighting air resistance at the same time, which requires unreasonable energy density

    If only there was some way to use air resistance to fight gravity, or better yet even some sort of metal road to push against to lower required acceleration to the minimum...

    Maybe if we made a super slow missile on rails? Never mind, this sounds crazy now that I say it out loud

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  • [–] 9 points 2 years ago (2 children)

    I think in that case, the earth would just depart the location of the train, leaving it drifting in space.

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  • [–] 2 points 2 years ago

    I was assuming the rails are strong enough to keep the train on the Earth, but I guess infinite friction from the movement and rotation of the Earth probably isn't survivable by any railway material. Hypothetically, if you had a material unaffected by gravity (train), and a material that is absolutely invincible (the rails, and they are anchored to the center of the Earth), now does it work?

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  • [–] 7 points 2 years ago*

    No, the problem is not gravity, is that the train attached to earth has velocity dictated by the Earth movements, and keeps it because of inertia. In your theoretical experiment, the train would be launched on space at constant velocity.

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  • [–] 4 points 2 years ago

    The problem isn't gravity, it's friction. The train would functionally be in orbit. The reason why things can't be in orbit at ground level is not because of gravity but because of friction (incl. air resistance).

    If you eliminated friction (vacuum tube, frictionless surface, etc.) you could indeed have the train moving without any additional energy after getting it up to speed (and if you get it up to orbital speeds, the frictionless surface isn't even necessary). However, this isn't really practical (obviously).

    If there is a nugget of a good idea in here, it's a train that never needs to accelerate or decelerate, just maintain a constant speed. Much of the energy of a train is lost in the stop-and-start.

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