I'm thinking the bottom of the slinky hits the ground in the same time after dropping as it would if it was not attached to a spring, or if it were the bottom of a rigid object of the same weight and aerodynamics dropped at the same time.

The bottom ring is motionless until the compression wave hits it, then it accelerates faster than gravity to the average -V of the wave. They should do a video showing it next to a rigid object.

the center of mass of the spring falls at about normal speed, it just moves relative to the bottom as the spring compresses. There is probably some effect from the stored energy too.

my prediction for the tennis ball experiment: the bottom will behave similarly but for a shorter time since the center of mass is closer to the bottom because of the ball. the stored energy effect will be greater because it is stretched more.

"It" doesn't "get" any information...

Depends what you mean by information.

>> ^Peroxide:

"It" doesn't "get" any information...

>> ^Peroxide:

"It" doesn't "get" any information...


I found this really damn irritating, too. Why must so many physics explanations ascribe will/consciousness to the objects in question? It comes off as condescending to me, like the physicist feels as though he's talking to a child.

>> ^budzos:

>> ^Peroxide:
"It" doesn't "get" any information...

I found this really damn irritating, too. Why must so many physics explanations ascribe will/consciousness to the objects in question? It comes off as condescending to me, like the physicist feels as though he's talking to a child.


Calm down, it's only a visualization technique. It's the way most physicists actually think about the problem too, even though the actual physical processes are far more complicated. The reason we do that is because it is easier, and it works.

Physics, with all the underlying jumping and jittering of atoms and molecules, is hard. Most physics phenomena are impossible to describe starting from the underlying quantum field theory. That's why we describe the world using other concepts such as temperature, pressure, and elasticity. They explain the world at higher level in the hierarchy, but that doesn't make them any less real. In the same vein, propagation of information is a useful concept for explaining many phenomena, but that doesn't mean we ascribe any consciousness to the object in question.

It's the Looney Tunes Effect. A character that runs off a cliff will not fall until he realizes he's only standing on air.

>> ^quantumushroom:

It's the Looney Tunes Effect. A character that runs off a cliff will not fall until he realizes he's only standing on air.

Yes! Just like Roger Rabbit can only escape from the handcuffs when it's funny to do so.

It's fun for a girl and a boy!

You can see it pretty clearly even without the slow-mo.

Now you're being condescending. "It gets the information and knows to fall" is nonsensical handwavy shite that doesn't really explain anything to a layman.

>> ^Ornthoron:

>> ^budzos:
>> ^Peroxide:
"It" doesn't "get" any information...

I found this really damn irritating, too. Why must so many physics explanations ascribe will/consciousness to the objects in question? It comes off as condescending to me, like the physicist feels as though he's talking to a child.

Calm down, it's only a visualization technique. It's the way most physicists actually think about the problem too, even though the actual physical processes are far more complicated. The reason we do that is because it is easier, and it works.
Physics, with all the underlying jumping and jittering of atoms and molecules, is hard. Most physics phenomena are impossible to describe starting from the underlying quantum field theory. That's why we describe the world using other concepts such as temperature, pressure, and elasticity. They explain the world at higher level in the hierarchy, but that doesn't make them any less real. In the same vein, propagation of information is a useful concept for explaining many phenomena, but that doesn't mean we ascribe any consciousness to the object in question.

It was not my intention to be condescending, only to explain why the physicist uses the words he does. Tell me then: What kind of explanation would you prefer? I'll do my best to oblige you.

>> ^budzos:

Now you're being condescending. "It gets the information and knows to fall" is nonsensical handwavy shite that doesn't really explain anything to a layman.

Explain why you're being a cunt.

>> ^Ornthoron:

It was not my intention to be condescending, only to explain why the physicist uses the words he does. Tell me then: What kind of explanation would you prefer? I'll do my best to oblige you.
>> ^budzos:
Now you're being condescending. "It gets the information and knows to fall" is nonsensical handwavy shite that doesn't really explain anything to a layman.

Video: cool
Explanation: weak
Tennis analogy: false

Better explanation: Initially, gravity is pulling the whole thing downward while the hand pulls the top upward and the rest of the slinky pulls itself upward and downward creating a balance. Then the old dude lets go of the top. The force pulling up on the bottom still exists, but it is now balanced by accelerating the top downwards faster than just gravity (notice how the slinky slows down as it collapses and loses force. As long as the coils are still taut, the upward force pulling the bottom of the spring up is the same. The top is now falling (being pulled down, actually) instead of pulling the old dude's hand, but the force in the spring is the same.

My guess is that a solid object dropped from the height of the middle of the slinky would hit the ground at the same time as the slinky did. But is that the middle point of a slinky stretched like this one (the top is stretched more than the bottom), or the same middle as when it's all neutral.

Tennis: With all the flex in a tennis racquet's webbing, the the player may feel the ball while it's still on the racquet, before the webbing shoots the ball back out again, but certainly long before it gets to the net.

http://www.youtube.com/watch?v=QvZ7prb43Lk (watch the vibrations in the racquet)

*timeshift

Adding video to channels (Timeshift) - requested by lucky760.

nice jeggings

no way. there is was a planned demolition. you can tell by the explosions at points throughout the columns. That metal is built structurally so as to not collapse under its weight.

http://en.wikipedia.org/wiki/Jeggings>> ^residue:

nice jeggings

um...yes?

>> ^dystopianfuturetoday:

http://en.wikipedia.org/wiki/Jeggings>> ^residue:
nice jeggings

fuck neutrinos, I think we should look further into this phenomenon

It seemed simple to me, the 'upward' force created by holding the top of the spring collapses at 9.8m per second per second. This equals the force of gravity on the portion not yet collapsed. With the forces canceling each other out, there's no movement.
A ball will fall faster, not due to any spring force but due to simple air resistance, which is higher on a spring than a ball. Now done in a vacuum they should fall at the same rate (measured at their center of gravity).
I also hate the personification of physics forces in efforts to incorrectly explain them to those that can't understand. It often leads to MORE confusion rather than less.