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submitted 1 week ago by [email protected] to c/[email protected]
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[-] [email protected] 9 points 5 days ago* (last edited 5 days ago)

When I was a kid I came up with this design during a long road trip. I spent the whole time thinking I was some kind of genius, because how didn't anyone else think of this before?

You can imagine my disappointment when I got home and created my prototype.

[-] [email protected] 21 points 6 days ago

Because you need to put it on the back and have it repel the truck forward instead of attract it forward obviously

[-] [email protected] 6 points 6 days ago

This works in Kerbal Space Program

[-] [email protected] 3 points 5 days ago

Equal AND opposite

[-] [email protected] 111 points 1 week ago

Young lady, in this house, we obey the laws of thermodynamics!

[-] [email protected] 45 points 1 week ago

Did you try flipping the magnet over? If you put the two north ends together they’ll repel instead of attract.

[-] [email protected] 11 points 1 week ago

The beauty is that you can make the mental gymnastics to make it work both ways.

If they are opposite, the magnet attracts the car which moves the magnet away creating infinite motion

If they are the same, the magnet is repelled by the car, moving it away, moving the car forward creating infinite motion

You can even do mental tricks to make the contraption go backwards: Opposites: car attacks magnet which moves the car backwards Same: magnet reppels the car which moves the contraption backwards

[-] [email protected] 9 points 1 week ago

By your though process shouldn’t the car be going backwards?

[-] [email protected] 29 points 1 week ago

I tried something like that when I was about ten.

[-] [email protected] 18 points 1 week ago

I still hold feelings against the force range being so short. Too close and the wire bends. Too far and there is barely any attraction...

Ugh, I just want to break physics, let me be.

[-] [email protected] 19 points 1 week ago

It would work if the repulsion/attraction only went in 1 direction. But since it goes both ways, they just cancel out.

Conversely, the fan version of this idea (fan blowing into a sail) does actually work. But it's nowhere near as efficient as simply turning the fan away from the sail to push you the normal way.

[-] [email protected] 3 points 5 days ago

What if u put the fan in the water?

[-] [email protected] 2 points 5 days ago

There's oxygen in water, so it could work

[-] [email protected] 4 points 1 week ago* (last edited 1 week ago)

Well because there the whole system now becomes the ship+air/water molecules rather than just the ship + you use energy to work the fan which imparts that energy to the air/water molecules. In the end the air/water molecules literally get pushed behind so the rest of the system can move forward.

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[-] [email protected] 19 points 1 week ago

The wire/metal holding it needs to be springy and bobbing back and forth to generate the momentum, duh.... Half-assed implementation I say.

[-] [email protected] 18 points 1 week ago

Excellent! It is always nice to see people asking questions - the journey towards the answer should prove most enlightening! :-D

[-] [email protected] 16 points 1 week ago

The magnet isn't strong enough.

[-] [email protected] 14 points 1 week ago* (last edited 6 days ago)

If you ever talk to someone confused by this, maybe ask them to lightly push the front magnet in the direction it's trying to go.

[-] [email protected] 5 points 5 days ago

I tried that, nothing happened to the picture. why???

[-] [email protected] 3 points 5 days ago

Huh, try putting it next to the phone

[-] [email protected] 12 points 1 week ago
[-] [email protected] 4 points 1 week ago* (last edited 1 week ago)

Why would it? Think about it, would the two magnet gets closer if the wheels started rolling?

[-] [email protected] 12 points 1 week ago

Not with that attitude they won't.

[-] [email protected] 11 points 1 week ago

Need a bigger magnet.

Also, how do they work?

[-] [email protected] 12 points 1 week ago

Real, totally heavily simplified answer. All atoms could be magnets, but most don't have a force because the electron orbitals aren't out enough. In fact just about everything can be explained by what the electron orbitals are doing. Even why the chair you're sitting in feels solid. It's the orbitals. See Richard Feynman's bit on magnets and the deeper lesson on knowing the right questions to ask.

[-] [email protected] 3 points 1 week ago

I love listening to Richard Feynman talk in those interviews

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[-] [email protected] 7 points 1 week ago

they come from the ground so they have gravity in them

[-] [email protected] 5 points 1 week ago
[-] [email protected] 2 points 1 week ago* (last edited 1 week ago)

I am pretty sure the other guy is talking nonsense and he kinda didn’t explain anything, its basically an atom with such a subatomic structure where there are more electrons on one side than the other, making that side more negative! The whole deposit is made up of atoms facing the same way!

https://encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcQ7plIgcsKhof-nwcD7OcmJvJcNqtpjmpJjTA&usqp=CAU

https://www.coolmagnetman.com/images/maghow23.jpg

[-] [email protected] -2 points 6 days ago* (last edited 6 days ago)

Oh boy, this is very incorrect, because it sounds like you are attempting to explain magnetism with electrostatic forces. Here is a basic model which separates the difference between the two:

  1. Electrostatic forces are caused by the electric field. Something produces an electric field simply by having an unbalanced charge. Positive attracts negative, negative repels negative, positive repels positive.

  2. Magnetic forces are caused by the magnetic field. Something produces a magnetic field by having an unbalanced charge AND is moving.

This is why when trying to explain how solid magnets work, we focus on the electrons because electrons are charged particles that are always moving. So they produce both an electric field (being charged) and a magnetic field (being a moving charged system).

Rhaedas is sorta correct. Any solid system has the capability of being a magnet, but this takes an incredible amount of physics work where iron is special. Iron's electrons are able to easily maintain a synchronous orbit with each other which results in magnetic forces being observable at a macroscopic scale (seeing iron magnets pull on each other). In most other materials, the electrons orbits are chaotic, so even though magnetic fields are still being produced by their electrons, the lack of order results in no magnetic force being observable on the macroscopic scale; but if you place this non-iron material within a very strong magnetic field, you may be able to align their electrons orbits so that it becomes magnetic on the macroscopic scale (like iron).

[-] [email protected] 0 points 6 days ago* (last edited 6 days ago)

Did you use ai to form that? No human has ever, ever written that magnetic force causes magnetic field; nor electrostatics force causes an electric field…

No, electrostatic fields is caused by stationary charges

I don’t dare imagine what you think an unbalanced charge is, but a moving electric charge is enough to cause a magnetic field.

‘It takes incredible amounts of physics work to get something’… You know, ai used to worry me quite a bit but comments like yours calm my soul! We are thankfully not there yet where it’s actually would be capable of replacing hack squat!

[-] [email protected] 3 points 6 days ago* (last edited 6 days ago)

Lol you weren't kidding... The full sentence is even weirder:

Any solid system has the capability of being a magnet, but this takes an incredible amount of physics work where iron is special.

I kind of hope a human didn't write that...

[-] [email protected] -1 points 5 days ago* (last edited 5 days ago)

Not AI. I'm in academia, so I write academically.

I specify "physics work" to mean physic's definition of work (dot product between Force and Displacement).

And to not connect the importance between the electric and magnetic field as it pertains to the the electrostatic force and magnetic force reveals your basic understanding of the physics. Hence, why your prior comment was so problematic...

[-] [email protected] 0 points 5 days ago

Oh academia! Of course you are! Kinda weird you didn’t specify your field and experience… Welp, must have had no space left for that in that reply of yours…

Kinda odd that an academic would continously write nonsense… Work in the contest of physics (what fucking other context would we use it when we are discussing physics…) is defined as: the energy transferred to or from an object by a force acting on it as it moves through a distance!Aka ‘W = F • s’, its not a dot product its multiplication dear doctor? Also makes absolutely no sense in the prev context you used it… If you just wanted to pick a word to insinuate a sort of insight, you should have used midi-chlorians! Sounds a lot cooler and makes just as much sense!

So far every single one of your statements had been wrong… I will have to ask you to stop sharing your brilliant insights to beget the spread of misinformation!

[-] [email protected] 0 points 5 days ago

It's very apparent that you are not a good faith discusser and your knowledge of physics is very low.

I'm checking out of this discussion

[-] [email protected] 0 points 5 days ago

Could you check out from every physics&whatever else you pretend to be discussion? Again, you didn’t even know the formula of work despite totally being an academic…

It genuinely upsets me that people like yours vote equal mine… Hope you know you looked really dumb and desperate the whole time!

[-] [email protected] 1 points 5 days ago* (last edited 5 days ago)

I used the higher level 3-dimensional definition of work, and you told my I was wrong and provided my the high school level 1-dimensional definition of work. Then you hang it over my head and try to correct me as if my definition is incorrect.

The fact is your knowledge of physics is so low that you didn't even know this nuance; and you are not arguing in good faith because this is something you easily could have looked up and realized if all you cared about wasn't "being right".

[-] [email protected] 1 points 5 days ago

Heeeey! Now you only need to look up what dot product is!

[-] [email protected] 1 points 5 days ago
[-] [email protected] 1 points 5 days ago

Love, you are an actual embarrassment!

Look up what a dot product is!

[-] [email protected] 8 points 1 week ago

Needs more magnets and some springs.

[-] [email protected] 7 points 1 week ago

Maybe it needs gas?

[-] [email protected] 4 points 1 week ago

need two separate vehicles and two magnets, one weaker then the other

so the weaker one will repell the other and it will kick forward moving the other forward and rinse and repeat at a sonic speed

thats gotta generate some kinda motion

[-] [email protected] 9 points 1 week ago* (last edited 1 week ago)

This is basically how a ~~rail cannon~~ coil gun works, just with electromagnets that can reverse their polarity.

It's a powerful way to accelerate anything — I think it's most famously used in those types of metal roller coasters that start you at a flat-with-the-ground angle, and then just fuckin launch you up a ramp to 45° with electromagnets. The issue is that you need a fuckton of energy to do that.

What we need for true perpetual energy is to just capture that guy Blanka from Street Fighter.

[-] [email protected] 1 points 6 days ago

What we need for true perpetual energy is to just capture that guy Blanka from Street Fighter.

Surely that dude has to eat a lot in order to produce so much energy, no? Or is it just all stored somewhere in his body?

[-] [email protected] 6 points 1 week ago* (last edited 1 week ago)

That's not how a railgun works, that's how a coilgun works. Railguns create a loop of electric current that flows into one "wire" (the rail), through the projectile into the other wire, and back down to the starting point again, this configuration creates a force that pushes the projectile down the rails

[-] [email protected] 5 points 1 week ago

Ah, I appreciate the correction. I'm not an engineer but the youngest cousin of a clan of them, so I just got the highlights of the true evil genius shit. :p

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this post was submitted on 04 Jul 2025
505 points (99.2% liked)

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