Was wondering if it would be possible to create a magnetic field around cars that would make it almost impossible to physically bump into another car.
I am thinking how two magnets, polar opposite, react and thought that would be a way to ensure no fender bender in parking lots, or other lower speed crashes. Your cars could never really touch another.
Granted, I doubt this would work in a head on collision at 90 MPH, but for low speed, city driving - or just backing out of parking spots and other situations, would it be possible to have an electronic magnet gizmo that would keep car from causing damage?
I’m sure the power requirements would be insane in any case, but you could have it only engage when an impact was imminent. And both cars could do an electronic handshake and they could determine their polarity randomly.
I doubt that any reasonable electromagnet would actually repulse another car though.
What happens to the energy? When these two magnetized cars approach each other at speed, won’t the magnetic forces bend the metal just as the impact would have? You might still save the paint, though as there would be no scratch.
Not only would you need to be able to exert huge forces with the magnetic fields, but you’d have to do it at extreme distance. The way such a device would decrease damage would be to spread out the distance over which the impact occurs. Even with modern cars with crumple zones, where the entire front end of the car folds up like an accordion, people still get badly hurt in crashes. So you’d need the field to extend in front of the car a significantly greater distance than the length of the hood. I’m pretty sure that nobody has ever made a magnet that strong, not even in controlled laboratory situations.
Wait, for two or a hundred cars, you still want them all to be the same. You agree to it and set it up at the factory.
ETA: You just agree that all cars will be North and there is no need to guess from then on. Good luck taking your car on the chunnel to England where they build them all South.
Well, if you manage to make a magnetic monopole an actual reality instead of a purely hypothetical structure, you might be in business; but you’d probably win yourself a Nobel prize in physics as well.
And here I was afraid of getting whooshed-- I really did think you were probably joking. OK, the short form of it, then: Make a big ball of North-pointing-out magnets, let’s say it’s a meter in radius. If I stand next to it, I have a few norths right next to me, some further away, and some as far away as 2 meters away. Meanwhile, I have a bunch of souths, all of them 1 meter away, none of them any closer, but neither are any of them further away. Which is stronger, the norths, some of which are close but some of which are far away, or the souths, which are all at a middling distance? If you do the math (most easily accomplished via Gauss’s Law), you’ll find that the norths and the souths both have exactly the same effect, anywhere outside the ball, and you’ll end up with no magnetic field at all.
Magnets? Not a good idea at all. The car-collision prevention projects I see these days are all using computer-controlled driving assistance coupled with radar detection.
Try playing with some really powerful magnets sometime and it will quickly become clear that this idea could never really work. When two like poles approach each other, there is not only repulsion, there is also a very strong tendency for them to flip around so that they are not facing each other with like poles any more.
Even if it were possible to do this with some kind of array of active electromagnets, there are still problems:
The strength of a magnetic field is generally inversely proportional to the cube of the distance from the magnet - this means that in order to exert forces useful enough to ameliorate the effects of two just-about-to-crash vehicles, the magnetic field would have to be extraordinarily powerful - at the moment, this would mean huge, heavy helium-cooled superconductors, plus something porobably at least equally huge to power them.
And as previously mentioned, a magnet powerful enough to prevent two speeding cars from colliding catastrophically will turn smaller ferrous objects into lethal missiles. Magnetically cushioning a car from impact will be of no comfort to the driver if the same magnets yank a can of soup out of the shopping in the rear footwell and pull it through his ribcage.
I figured it would be along those lines. Still, that is true for an ideal setup. Imagine now a car lined with magnets all norths pointing out. And the magnets weak enough that the far side of the car is irrelevant (thus useless for collision prevention). Would that work?
I would think Chronos’ point doesn’t depend on the strength of the magnets . . . if you weaken them in hopes of being able to ignore the far side, you’re weakening the near side as well. So now you just have a smaller value canceling out a smaller value instead of a bigger value canceling out a bigger value.
Wouldn’t the magnets be subject to an equal and opposite reaction? The force they pushed apart with would send the actual magnets slicing through the car with the force of the momentum each car carries, wouldn’t it?
