Slinky Drop Answer

[Mandems]

"And as always, thanks for watching."

[jondunmore]

So THATS why the Coyote can run on air for a few seconds before he realizes he's run off a cliff and falls.

[veritasium]

It is a suitable alternative but I wouldn't say it is better. Personify has another meaning 'to embody, ' which is not what I meant so it is less clear.

[untitledname]

I have really three important points to explain

. . .

[veritasium]

I'm not sure what you're asking but the release dates of the videos may be your answer.

[veritasium]

@Soundslikehope We dropped the longest slinky we could find - I think it's pretty impressive. It's linked in the description.

[veritasium]

@valentine446 your comment is obviously true. But sometimes we anthropomorphise objects to help others relate to the physics.

[samad]

Actually the answer "end didn't notice" is untheoretical let me explain why the end of spring remained stationary:
When you hold one part of the spring in your hand and allow the second end to elongate as much as it takes to reach equilibrium both the weight force and spring force will be equal (note that the spring force is -k(L2-L1) or (stiffness) x (elongation)), so the only variable for the spring force is elongation.
To have an equal force to its weight it needs to elongate until delta L times K is exactly equal. Now when you drop the upper part it will be pulled by spring force and weight hitting the other end to create a down force and with the impact of both ends the spring force will reach zero and the weight force will be the only force on the system.
To make things simple think of a spring stretched horizontally on a table with hands holding each side and release one side you will not feel any change in forces in the hand holding the spring until the other side hit causing an impact force.
For the ball question, If you attached weight to the end the weight will make an equilibrium by extending the elongation but if the weight is much more than the spring elongation can handle it can't make an equilibrium thus the spring will move downward before getting together.

[FrzyBast]

My intuition would be to say yes. Think of the two ends of the slinky as separate masses. When the top one falls but the bottom one remains stationary, the top one will gain some momentum. When they meet and fuse, that momentum is transferred to the combined mass, which gives it an initial velocity. Then it falls according to gravity and builds up the velocity it would if you just dropped the bottom end.

[pickledmagnolia]

The tennis ball will stay in place (until the wave hits it) because if gravity is pulling it down more because of the weight of the tennis ball, then gravity is also causing the slinky to experience an equal amount of tension. The ball is causing a greater tension force as well as a greater pull of gravity, so the opposite and equal forces cancel out and leave the ball in its place.

[FlyaWhiteGuy]

"Slinky not long enough?"
Don't they sell pills for that?

[MrJenlai]

I don't agree with the explanation when it said that the information need to travel all the way to the tennisball to "tell" it to drop. When the slinky just hangs in the air, the gravity pulls it out and gives it a tension that wants it to contract. Due to the gravity that is affecting the whole slinky. When the top part is dropped the tension is released and the slinky is trying to contract to its usual state. And while gravity still affecting the slinky it makes the top part accelerate with a greater speed then "freefall" on that mass should. Due to the tension in the slinky. The same tension that keeps the bottom not to start accelerating before the up tension is low enough to let gravity affect its acceleration. Same goes for the tennisball that makes the slinky extend longer and increases the tension to keep it in a lockes position. I can think of a few experiments that would show this. Greeting //Niklas Björling, Sweden

[Meter]

I have a question.  What would happen if the object dropped were not in a state of tension, for example: a chain.  Are the results the same because the "message that the top has been released" not traveled instantly, or does the Slinky's internal tension play a major role?

[cometgravity]

I literally said "That is AWESOME!" during this video. Thanks for getting me here, Vsauce!

[Snwjunke]

Am I the only one that saw it clearly in the full speed portion?

[nO_dNAL]

Pretty cool. You can see it without slow-motion too

[veritasium]

yup I know the slo-mo guys. I didn't see the link in the description at first. I've actually made a better vid with a Phantom now: /watch?v=uiyMuHuCFo4

[veritasium]

I did at least three stories in Awesome HD slinky slo-mo

[Oops-All-Ghosts]

The reason golfers finish "with a nice little flourish" is because following through like that is a: good for your arm, and b: helps you know whether you've directed the ball properly; if you don't finish through well, chances are you haven't swung very well either. It has nothing to do with golfers thinking it has some magical effect on the ball. In general it is best to assume that other people aren't doing things for stupid reasons.

[vihangwagh]

Hey Derek! I have another argument ( a much easier one )!
Say, the bottom end of the slinky starts falling as soon as we let go... The whole slinky would be falling. As a result, more kinetic energy would be generated in this case than the actual one ( where it waits till the top end falls ). Since the total work done due to the gravitational force is the same, it means that the loss in ( spring ) potential energy is less in this case. However, this contradicts the fact that every system tends to the configuration of lowest potential energy!!