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Can Repelling Magnets Replace the Spring in a Pogo Stick?

kjmagnetics.com

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Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#71

Post by CydeWeys »

bleomycin wrote: post #51
Retric wrote: post #48

Earlier quoted context omitted.

Elevators use simple physical safety systems. Which is why you see headlines like: "Skyscraper elevator plunges 84 floors — and everyone survives" https://www.cbc.ca/news/world/elevator-plunge-chicago-1.4913...

Every link i’ve seen to this story annoys the hell out of me because they don’t explain HOW the elevator eventually stopped. That’s literally all I want to know.

It reached the bottom. Probably hit one of these: http://elevation.wikia.com/wiki/Buffers

Note that it wasn't descending particularly quickly; one cable snapped but other safety systems were still operable.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#72

Post by azhenley »

zaroth wrote: post #67
azhenley wrote: post #19

Earlier quoted context omitted.

About as scary as my Tesla on autopilot going around a curve at 75mph. Every time I ask myself, what if there is a bug or if it turns off...

I know exactly what you mean. I will admit at 20mph over the speed limit going over a poorly maintained curve on the Mass Pike I usually just disengage for a moment and then switch it back on. It can take the curve, but it doesn’t feel good to let it. I’ve had it lose tracking on the highway. It just leaves the wheel in the last position and beeps very urgently to let you know to take over. I find autopilot helps me…

I rave about how awesome it is too. In stop and go traffic it’s wonderful and rarely asks me to touch the wheel. I don’t like it for lane changing either so I always take over.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#73

Post by contravariant »

notacoward wrote: post #57
contravariant wrote: post #56

Earlier quoted context omitted.

A mechanism that absorbs any kinetic energy would make for a very disappointing Pogo stick.

If it absorbed all of the energy that would be a problem, but any child who has seen one of those science-museum displays I mentioned can tell that's not the case.

You don't really want a pogo stick to absorb any energy, it'd be like trying to make a pogo stick out of mud.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#74

Post by gonzo »

bleomycin wrote: post #51
Retric wrote: post #48

Earlier quoted context omitted.

Elevators use simple physical safety systems. Which is why you see headlines like: "Skyscraper elevator plunges 84 floors — and everyone survives" https://www.cbc.ca/news/world/elevator-plunge-chicago-1.4913...

Every link i’ve seen to this story annoys the hell out of me because they don’t explain HOW the elevator eventually stopped. That’s literally all I want to know.

Entering “elevator safety mechanism” into google will bring up several links with explainations. The first link for me references this story.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#75

Post by nsxwolf »

bleomycin wrote: post #51
Retric wrote: post #48

Earlier quoted context omitted.

Elevators use simple physical safety systems. Which is why you see headlines like: "Skyscraper elevator plunges 84 floors — and everyone survives" https://www.cbc.ca/news/world/elevator-plunge-chicago-1.4913...

Every link i’ve seen to this story annoys the hell out of me because they don’t explain HOW the elevator eventually stopped. That’s literally all I want to know.

I’d also like to know what they meant by “plunges”. How fast did it descend? Was it in free fall?

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#76

Post by [deleted] »

jolmg wrote: post #64
gumby wrote: post #61

Earlier quoted context omitted.

Consider not going on a modern airliner. Every commercial passenger jet since the A340 has been fly-by-wire. (military jets have been so longer).

But you have more time to react on a plane and switch to manual override. It's not like people fly with just a few meters distance to other airplanes. There's also a good distance to the only other thing you can crash into, the ground, as opposed to driving between walls or with a cliff to one side.

[deleted]

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#77

Post by shagie »

truethrowa wrote: post #49

How can they stack three magnets with the repelling side facing each other on all three magnets? Isn't one side repelling and the other attracting?

You can do some interesting things with magnets. Consider the Halbach array ( https://en.wikipedia.org/wiki/Halbach_array ) often used for refrigerator magnets.

That said, the 3 magnet configuration would be:

NS - SN - NS

From the article:

> We added a third magnet, alternating which way the polarity faces with each magnet. Each magnet repels any adjacent magnets.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#78

Post by djsumdog »

bleomycin wrote: post #51
Retric wrote: post #48

Earlier quoted context omitted.

Elevators use simple physical safety systems. Which is why you see headlines like: "Skyscraper elevator plunges 84 floors — and everyone survives" https://www.cbc.ca/news/world/elevator-plunge-chicago-1.4913...

Every link i’ve seen to this story annoys the hell out of me because they don’t explain HOW the elevator eventually stopped. That’s literally all I want to know.

There was an elevator hacking talk that went into the buffers at the bottom of the elevator. You may have seen them in elevators that have glass on the outside of the shaft like in malls and hotels. The elevator never rests on those. Those are to take the impact of an elevator that crashes. Inspectors will often test the buffers as well as part of routine maintenance:

https://www.youtube.com/watch?v=ZUvGfuLlZus

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#80

Post by djsumdog »

Retric wrote: post #48
weberc2 wrote: post #28

Earlier quoted context omitted.

Pretty much every critical system in a vanilla Toyota is already software-controlled, not to mention the legion of critical systems involved in air travel, elevators, medical equipment (e.g., pacemakers), etc. Not sure that this should bring comfort, but at least you need not be particularly frightened by your Tesla. :)

Elevators use simple physical safety systems. Which is why you see headlines like: "Skyscraper elevator plunges 84 floors — and everyone survives" https://www.cbc.ca/news/world/elevator-plunge-chicago-1.4913...

What's deadly is the other type of failure, where the counter weight causes the elevator to shoot upwards, like what happened in that elevator in Chile. There's a video of the guy confused as the doors continued to open/close at each floor. He had severe injuries.

Apparently if that ever happens, your best bet is to lay flat on the floor with your hands covering your head, as the impact will launch you upward.

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