Can you make a pinball machine lighter with a magnetized handtruck?

Stuff it, removed the comment. I can't be bothered getting to a debate over physics >.>

Newton's Third Law. For every action there's an equal and opposite reaction. The weight of the machine doesn't just disappear, it's transferred to the magnetic whatever it's floating above. If you're just zipping it around over a magnetized floor, yeah, you won't have to exert force vertically (but you still will horizontally). If it's a wheeled hand truck with a magnetized bed, that hand truck's gonna weigh as much as that pinball machine, plus the magnetized hand-truck.

Yes because Vinny said so

Man, that hurt a little bit to listen to but whatever, I'd probably embarrass myself if I tried to talk about video editing on my hypothetical engineering podcast. @itwongo has it exactly right, thread's done.

This is the only acceptable answer.

it was pretty funny. The funniest was jeff having the right answer and explanation and being talked into uncertainty though.

I voted no, but the answer is "kinda".

While the machine is over the handtruck, you will perceive it being lighter (just the machine, not the whole "assembly"), but it'll be a bitch to keep there as the magnetic forces will try like mad to shove it away in multiple directions.

If you:

• demagnetise the handtruck and machine
• lift it onto the handtruck
• find a way to chain it in place
• THEN megnetise both

because it is levitating, you will find the machine easy to jostle as if it weighed much less.

However, moving the handtruck in any circumstance would be just as hard (if not harder due to moments of inertia) whether the machine is magnetised or not - disregarding the weight of the magnets themselves, as Jeff rightly mentioned.

Think of the magnets repelling eachother as if you put a giant pillow between the machine and the handtruck. If you take a pinball machine and lift it onto a handtruck with a pillow on it and then try moving the handtruck, it'll feel pretty much the same as if there were no pillow if not slightly more tricky.

The total downward force on the wheels of the handtruck is about the same (with slight differences in rotational acceleration, etc, depending on circumstances). It's that force that matters when you are trying to pull it, not the apparent weight of the machine.

ED: For reference, I have an Aeronautical Engineering degree if that's worth anything to anybody.

Physics nerd checking in. Now lets say Vinny's idea of safe magnets would work not that they would lets say they do. No supposing that they exist and would not damage or let the machine slip the actual force of gravity is fighting against the force of repulsion of the magnets. Now that force does not dissipate as people think it does it is applied to both object and as the pinball machine is doing all the pushing against both gravity and the magnetic repulsion the force of gravity is applied directly to the repulsing hand truck dolly thing. Therefore it does not make the pinball machine light but it does make it higher and forces the center of gravity down therefore making it slightly easier to move (again supposing the magic Caravella magnets version 3.0 do indeed work) but it does not make the unit and handtruck any lighter.

Edit: PS Jeff was eerily correct from a physics standpoint making the floor magnetized (again in a way that would not damage the machine and so on) would actually allow you to move the pinball machine as it would float the problem then becomes it still weighs the same amount and getting an object with that amount of mass would take a good amount of work just as moving objects in space (0 gravity and in a vacuum) still requires a force that came overcome the opposite force of the mass of the object.

@haruko: "Overcoming the opposite force of the mass" is a really misleading way to describe inertia. You're also misusing the term "work" from a physics standpoint...in 0-gravity / ignoring air resistance you can move the machine with as little work (force times distance) as you want (though it may take a longer time). In the absence of non-conservative forces like friction, *any* non-zero force is enough to start accelerating an object (also ignoring deformation); inertia simply affects the magnitude of that acceleration.

The scarier part with the magnetized floor is stopping the machine once you've got it moving. Most likely someone is getting crushed to death or you're knocking a hole in your wall.

I like how a definite question with a concrete answer is in the form of a poll. I guess seeing what people think is interesting data in itself.

I love how stupid(ly funny) Vinny is sometimes. I don't intend to come off mean and hostile, but every now and then he tries to extend the concept past its logical conclusion. On a deeper level, it just reminds me of how cynical I can be, and Vinny's easy-go-lucky(?) attitude is representative of a sort of don't-give-a-fuck nirvana we should all strive for. But damn, sometimes Vinny says some dumb stuff. Still love that bastard, though. There's a reason that weekly NeoGAF thread has a Vinny Checker.

I'm not an Aeronautical Engineer, but I'll pretend I know just as much.

Do you think it's be correct to redefine your "kinda" as "the weight is the same, but there's a latency to the system that changes the perception of the weight"? The weight's still there (in a different form) but due to lack of physical contact, you're moving the handtruck, which moves the point where the magnets properly interact to enable the levitation, which then has to move the arcade machine. It's kind of like that question about a car with a ramp on top, dropping the ramp on the ground, launching, then picking up the ramp with its mechanical arms super quick - it's still a closed environment/situation, so the Third Law applies (like someone pointed out above).

You are absolutely correct in my misuse of terms but also I haven't taken a physics class in 8 years so there's that. Also I would pay to see someone actually so this with a massive magnet floor and a large magnet.

Anyone saying you can't haven't experienced the Caravella Mag systems, available in all fine Mag stores.

Assuming the you somehow figure out a way to steadily place the arcade machine onto the magnetized hand truck without the machine flying off in a billion different directions, I'm fairly certain the answer would still be no. The upward force being generated by the hand truck in order to levitate the arcade machine would be matched by the downward force the arcade machine would be generating back onto the hand truck. Meaning the hand truck would be pressed against the earth making the strength required to push the hand truck essentially the same as without the magnets.

Now if the floor was magnetized with an opposite polarity to the arcade machine directly, then the machine would essentially be floating in the air pushing back down against the earth itself. There would be no middleman hand truck. This is essentially the principle of how magnet trains work.

Jesus Christ, that conversation they had was pretty bad.

It can be boiled down to "While standing still upon the handtruck the perceived weight of just the machine will be zero, but in every other way Vinny, you loveable bastard, no" - the idea of latency would only come into effect when trying to move the handtruck, and that would depend upon the elasticity of the "chains" keeping it from flying off.

If you were keeping the machine in place using a tight fitting steel cage, for example, there would be little to no latency when trying to move the machine. However, if you are using big rubber bands with a bit of give, then yeah, there'll be a latency to the system upon movement and many follow-on effects due to inertia. I'm not familiar with that specific car analogy, but it sounds fun.

Complicated stuff aside though, it comes down to the difference between "perceived weight" and "weight", and what you are judging it by - pulling the machine (a sub-system) or the handtruck (the complete system).

This makes about as much sense as the joke image where one guys lifts a person into the air, then the other hoists him up, allowing those two to travel to space unaided.

High-School-Physics-Free-Body-Diagram Time! Free body diagrams are used to show forces on one or more objects.

Here, we see a (really shitty MS Paint) free body diagram, Where G is the force of gravity on the the block at its centre of mass, and N is the normal force of the ground on the block.

The force of gravity is probably easy to understand (stuff falls down), but what exactly is the "normal force"? Well, the block isn't falling though the ground, is it? If the ground wasn't there, it would just keep falling, right? So, because the block is stationary (ie not moving, or more importantly accelerating), this means that the ground has to be applying a completely equal and opposite force on the block! The equal and opposite phrase might be familiar to some of you, as it's Newton's Third Law of Motion.

So, what would a free body diagram look like if we wanted to easily move around a pinball machine with giant electromagnets?

Here, the two G forces are the force of gravity acting on the handcart and the pinball machine, N is the normal force of the handcart on the pinball machine, and M is the collective magnetic forces pushing the cart up and away from the ground.

To levitate the handcart and its load, off the ground and into the air a particular distance, these magnetic forces must be larger than the forces of gravity on the handcart and its load. When the handcart is in the air at a particular distance, the magnetic forces have to be equal to the collective forces of gravity. You would then, theoretically, be able to push around the handcart horizontally with ease.

The floor would have to be magnetized (somehow), as would the handtruck.

So, what I'm getting at, is the the theoretical physics is there, BUT it's going to be impractical, prohibitively expensive, and possibly destructive implement.

What about doing it Vinnie's way?

Here, N is the normal force of the ground on each wheel, G is the force of gravity on the handcart and the pinball machine, and M is the force of magnetism on the pinball machine and the handcart. You'll notice the magnetic force pushing up on the pinball machine is also equally pushing down on the handcart, much like Normal forces do. So, as you move the handcart around, you would notice that it fells just as heavy as if you didn't use the magnets at all. Actually, it would be heavier, because of the installed electromagnets.

Someone should photoshop some Juggalo paint on Vinny's face with him asking how magnets work. Because of the internet.

I'm just an undergraduate Electrical & Computer Engineer but even that side of me says it's totally not going to work. It totally wouldn't be worth it but it would totally be worth it.

Also, someone is making an attempt:

https://twitter.com/JamesLeffler/statuses/359815369780772864

I aint no physicist but wouldn't there still be force pushing down on the bottom magnets? So you would still be dealing with the same weight?

Yes, exactly.

The handcart is the breaking part of the logic. If you just completely levitated the entire thing so there was no contact with the ground, you'd eliminate a significant amount of resistance in the form of friction. This would be most noticeable as static friction would no longer be an issue. It would be easier to move if you could stabilize it, but it'd also be harder to stop it, so it's not much of a gain without a good system in place to augment your ability to stop it. Also, it'd just fall and flip out in a really fucking dangerous way, and be very difficult to control, especially once it got moving and it was all momentum without anything but the resistance offered by the air and a few other relatively minor forces.

I can speak from experience: it's way better for something heavy to be too hard to move than for it to be way too easy to move and therefore way too hard to stop.

I'm pretty sure he was at most bordering on seriousness. It was clearly a goof.

Nope because you're going to get kicked in the balls by basic Newtonian physics. Generating the amount of force required to counteract the effect of gravity on the mass of the arcade machine will also great an equal counter force in the opposite direction. On a maglev train this doesn't matter because you're simply driving that force down onto the tracks but in the case of Vinny's hand truck you are pushing all that force down onto the bed and wheels. The end result is that for all intents and purposes it weighs just as much but now with all the additional weight of the electromagnets that you bolted on to everything which just makes the situation worse. And lets not forget that you now have zero friction which means that thing is liable to fall the fuck off the truck if someone as much as sneezes in it's general direction.

@selfconfessedcynic:

Okay, that pillow explanation really helped me grasp this completely. Many thanks

Also, did this discussion make any other nerds think of the hovering Han Solo being escorted through Cloud City?

Totally fine if it was just me, but I just spent like 10 minutes finding an image of that so damned if I wasn't going to post it.

@darknessmyoldfriend:

i don't know how to use photoshop

I voted no, but the real correct answer is "Yes, but it only works for Theater of Magic machines, BECAUSE MAGIC."

@tajasaurus said:

@darknessmyoldfriend:

i don't know how to use photoshop

Works for me!

The Mag lift on a monorail makes it "frictionless." not "weightless". The idea would make frictionless movement like if it was on ice.

So yeah if the magnets were not going to fry the arcade cabinet sure put them on slide it around you got it working right on the proper surface. Just once its in his truck, all that weight it still in there even more.

@tajasaurus said:

i don't know how to use photoshop

Glad to see that Giantbomb is home to a buncha smart people. The best part is that they aren't total asshats at the same time!

@jarmahead Glad to see that someone finally mentioned friction, because that is the real reason Jeff's idea of magnetizing the floor would actually work, (in an extremely idealized theoretical situation).

This principle is used in maglev trains and lets them move at high velocities at much higher energy efficiency than traditional trains. So yes, it has already been thought of.

@itwongo: If the floors were magnetitzed along with the pinball machine the floors would support the weight and although it would be tough to push it would still be frictionless thus making it easier than just a handtruck.

Lol, I don't know about that but hey check out this. Its the Escalera automatic stair climbing dolly. As someone who owns a few pins I would love to have one of these when moving machines.

http://www.escalera.com/

You guys haven't mentioned the first massive hurdle that any magnetic levitation system has to clear, namely Earnshaw's theorem. It states that magnetic levitation using only static magnets is impossible. Not just hard, but impossible.

In other words, if you take two kitchen magnets, you can't levitate one over the other. The one that's on top will either flip over and snap to the bottom one, or fall off to the side. You might think that if you had, like, fifteen different magnets, you could put them in some configuration where one magnet would stably levitate, but you can't, it will always fall to the ground or snap to one of the magnets. In other words, doing this thing only works with superconductors, not regular magnets, which is why that particular thing is always the first thing people show when they show a superconductor.

Now, there are plenty of loopholes. For instance, if one of the magnets is rotating (like this thing), or if you physically restrict the thing you're trying to levitate (i.e. something like this), it could work. But if you imagine Han Solo being transported through Cloud City, that would not work with just regular magnets of opposite polarity. Han Solo would either flip over, or fly off into the sky, or something.

That is to say, to even begin to consider Vinny's plan, you would need a vastly more complex system than just "the floor is one polarity, and the pinball machine is the other".

I loved this conversation, and now I love this thread.

This is gonna be the airplane-treadmill thing all over again, isn't it.

Nope, and a fan attached to a sailboat doesn't work either.

... But, man, wouldn't it be cool it these kinds of things did!

Also, I love Vinny.

EDIT: I just remembered that I'm a late listener this (last) week.

I actualy own that "The way things work" book, it is not in good condition, and is like 15 years old. though.

What if they just put down a magnetic track and made it a monorail or something?

Lighter, no. Easier to drag, yes.

Bolt magnet on truck and one on the bottom so that they repel each other. Magnets reduce normal force between arcade and floor, reducing friction proportionally. Machine turns into ice puck. But like @gkhan says, you'd have to keep the machine up.

Also, aren't magnets going to wreck havoc on the PCBs somewhere in the machine?

@kierkegaard said:

@selfconfessedcynic:

Okay, that pillow explanation really helped me grasp this completely. Many thanks

Also, did this discussion make any other nerds think of the hovering Han Solo being escorted through Cloud City?

Totally fine if it was just me, but I just spent like 10 minutes finding an image of that so damned if I wasn't going to post it.

I am going to assume the floor of cloud city is magnetized in some way to allow stuff to just float around on it and any carts or objects are stabilized in such a way that the polarity doesn't try to violently flip your cart or carbonized Hansicle whenever you try to push it around.

@kierkegaard said:

@selfconfessedcynic:

Okay, that pillow explanation really helped me grasp this completely. Many thanks

Also, did this discussion make any other nerds think of the hovering Han Solo being escorted through Cloud City?

Totally fine if it was just me, but I just spent like 10 minutes finding an image of that so damned if I wasn't going to post it.

In the Star Wars Universe, they are called respulsors.