ua question

Hello!  I've been visiting this site for some time now, I must admit it makes for some very interesting reading!   I'm a fan of space, and physics are very interesting, although I have no real education in either.  Just neat stuff to learn about in my free time.  My question comes from a video I saw on one of the other few websites I visit often.  I apologize beforehand, I've never joined a discussion board of any kind before, and I'm not sure how to embed a video or any of that fancy stuff, so I hope that this link will work. 

#ws" class="bbc_link" target="_blank" rel="noopener noreferrer">Slow motion slinky drop 1000fps

The video (hopefully right) is of a high speed camera capturing a slinky being dropped.  There are a few similar videos as well.  I suppose my question is for the topic of UA (I hope I'm right in believing that is when the earth is moving upward, as opposed to people and things being falling due to gravity?)  Should this video be possible with something like UA at work?  It would seem as though the whole thing should just fall at one time.  Again i'm not very well versed in science.  I appreciate any answers, and I do apologize if I somehow messed up posting and made it difficult to get to the video.

I have seen this before. I think I got there from a VSauce video on touch. Its pretty cool.
#ws" class="bbc_link" target="_blank" rel="noopener noreferrer">Slinky Drop Answer


UA is actually a theory developed by Albert Einstein based on the equivalence principle.

I'm sorry the guy below has had a charisma bypass, but at least its a neutral source.
#ws" class="bbc_link" target="_blank" rel="noopener noreferrer">General Relativity: The Equivalence Principle

Just awesome stuff.

Here's another good one.

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A slinky is a giant spring. When one stretches out a slinky and holds it from the top, the bottom end is being accelerated upwards by the tension in the metal. When one lets go of the slinky the bottom of it continues to accelerate upwards as the slinky contracts, since there is still tension in the metal pulling upwards, seeming somewhat stationary on camera until the mass contracts and collapses as a whole.

The bottom of the slinky may seem "stationary," but it is really accelerating upwards by the tension in the coil. This applies to both gravity and UA models. The presenters in the video even say that the bottom is being held up by the tension in the slinky in the Slink Drop Answer video, 'held up', of course meaning 'accelerated up'.

Lol I love thork's new term "charisma bypass".

Thanks for the second video.

Ah, I love slinkies.

I'm going to try to give a more general (if more complicated) answer to this question. It's really all a case of relativity. There's no difference between a person falling to the floor and the floor rising to a person. The only difference between those two situations is the frame of reference; whether you're observing the situation as the floor or the person. This gets complicated at high speeds, because light is weird, but a low speeds it's not that bad. In any situation with regard to UA and the Equivalence Principle, remember relativity. The solution may not be quite as intuitive as you hope, but if you think about it there will be a solution.

So in this particular situation, we need to look at what is happening from the UA frame of reference. The bottom of the slinky is being accelerated at 9.81 m/s². So is the top, starting off. But then the top stops accelerating, as it is no longer attached to anything. Now the bottom is going to stop accelerating, but it takes it a second. As for why, imagine the reverse. Hold a slinky still and then suddenly pull it up. It's going to stretch, because the bottom doesn't automatically change speed when the top does. It's the same principle.