Speed of Force or 'Transfer of Momentum'

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1. You need to be clearer. Number the events and describe exactly what they are. Are you saying Event 1 (action) is the first ball hitting the second and Event 2 (reaction) is the last ball swinging away from the group?

2. Clearly, you didn't read your own source. It contradicts you. Repeatedly.

[edit] The link describes in detail - without using the word "sound" - how sound propagates in a solid. The setup is approximated as a bunch of spring-mass systems, exactly as I described in my post about a single collision against a solid wall (just with multiple balls instead of one). Using the method described, you can generate a highly accurate simulation, including an accurate representation of the delay time between the first ball hitting and the last ball moving.

 

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I responded already, but here's an example from a quick google:

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http://demo.webassign.net/ebooks/hrw7demo/pc/c02/read/main/c02x2_10.htm

This graph shows the acceleration of a dummy in a rear-end crash test. It shows that from .04 to .1 seconds, the acceleration increases linear from 0 to 50 m/sec/sec. That's a constant jerk of 833 m/s^3. That's exactly the type of profile I was talking about.

 

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FYI, I think that bug has been fixed.

Anyway, I had a look at the thread. Oy, what a mess. Relativity? QM? Definition of Pi? Virtually none of the discussion is on point. This is not a complicated issue. The only reason it is an issue at all is that human perception time is too slow and some people are unwilling to believe anything they can't see with their own eyes (which begs the question: how can they be posting here/why aren't they terrified of their own computers?).

 

Looks like we are finally getting somewhere. Seems like my claims that a body wouldn't stay rigid in non-relativistic classical mechanics wasn't so crazy as it seemed after all. It was a concept proposed by Max Born, a life long friend of Einsteins, that must have made him really smart. Then to my surprise from a link in that page I found the Ehrenfest paradox that also is a concept or more accuratly a thought experiment in Special Relativity. It takes the spinning rod I mentioned that would turn to goo one step further by saying that it is not a rod but a disk, but it only concerns the effects of SR and not the speed of sound. I don't think we have discovered anyone yet that did actual experiments to prove the speed of transfer of momentum in a rigid body, but only some concepts and thought experiments in SR.

 

Yeah, it would be a surprise if they were actually on point.

Because computers let them go online and engage in fruitful *ahem* discussions on forums

These diagrams all show infinite jounce. lol.
Anyway, for such collisions there is finite jerk, but it doesn't prove that infinite jerk can't exist.

Just imagine a bored lab tech, messing around with super expensive high tech equipment. Maybe one day he records extremely high levels of jerk, and finds himself unable to limit the amount of jerk. Or perhaps evidence for infinite jerk will come from theory instead.

Nowadays particle physics doesn't really deal with jerk and jounce, so I guess this matter won't be touched.

 

Science doesn't prove negatives, only positives and never absolutely. But where it is now is as close as it can ever be to saying infinite jerk can't exist:

1. All theories that deal with the issue predict finite jerk.
2. All experiments that deal with the issue fit the theories.
3. No additional untested hypotheses exist that would show or imply infinite jerk.

 

Actually science does prove that certain phenomena can't occur. But as I previously said, no theories currently deal with infinite jerk, so its just a concept for now.


Okay, back to hansda.

The reason why the final ball doesn't receive all the momentum instantly is due to the presence of the three balls in between, which according to Wiki, makes for a very complicated system.

 

I guess you didn't bother to read the article, or maybe did not understand it, either way the paradox was resolved as pointed out in the article - so it is a non issue.

And you just continue to embarrass yourself.:shrug:

 

Funny you mention that because according to Einstiens equation the circumference of the disk should get larger. I would say that it has just has become an issue.

The article in the wiki on Born rigidity does not contain any maths, and says that it is only a concept , so then there would be no reason to think that it is actually science.

"Born rigidity, proposed by and later named after Max Born, is a concept in special relativity." I don't see how this could be made any more clear.

 

Consider this two ball Newton's Cradle as described in wiki:

Here the action(event 1) is when the left ball strikes the right ball. Reaction(event 2) is when the right ball strikes the left ball.

Here time-delay between action(event 1) and reaction(event 2) can be observed, though energy and momentum are conserved.

If more balls can be placed in between these two balls, time-delay between action and reaction will increase further as can be seen in five ball Newton's Cradle.

Yes. Right.

No. This is intermediate event where the last ball swings away. Reaction(event 3) is when the first ball swings away from the group.

Time-delay between action and reaction does not contradict Newton's Third Law.

So you agree with the time-delay.

 

So, there can be time-delay between an action and its reaction.

 

there is a time delay, but not between action and reaction.

It is between the so-called "bulk" movement of the initial and last balls, or the movement about the barycenter. Don't forget that metal is elastic, its shape changes and momentum is still conserved.

 

Like I said you apparently did not understand what you read. From your source:

Although the theory to resolve the paradox was understood by 1937, many subsequent authors have repeated various conceptual errors which had already been cleared up in earlier work, possibly because some of the explanations were not quite explicit.

I don't see how it can be made any clearer...

Born rigidity is a concept that helps to explore an aspect of SR, no objects actually have that property. I realize that this does not seem like science to you but then you do not have a firm grasp of what science is.

 

Howdy....Hello....This small note is also for the previous thread about gravity. Mass collides with mass, angular momentum collides with angular momentum, curvi-linear momentum collides with curvi-linear momentum. Any collision off of 180' is that amount of integer for friction. Now for fun and excitement consider that this occurs with structure prior to 'some' baryon, and that these acts help to 'create' baryon. Exactitude of geometry. (plus) Mechanical duration. Equal geometrical evolution. From a very flattened disk to a sphere. Force's squared to compressed compression pressure density. (gravity) There are other things that also form, but that is for another day. Hint: all of the standard forces, geometrically.

 

:fright:

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:bugeye::crazy::wtf:


You're Winner! :cheers:

 

Where is the time delay?

Do you mean action and reaction are simultaneous?

What is an action?

What is a reaction?

In the seven-ball 'Newton's Cradle', if the action is "first ball striking the second ball"; then what is its corresponding "reaction"?

How barycentre is connected with Newton's Third Law?

Is there any condition for Newton's Third Law of Motion?

 

So, i think now you agree that; there is a time-delay between an action and its reaction.

 

Good. You finally seem to be asking the right questions.

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It is Newton's 3rd Law. Body A exerts a force on Body B and Body B exerts an equal and opposite reaction force on body A

In classical mechanics, yes.

all the other balls will move (if they are touching), each ball may also elastically deform.

Barycenter can represent the momentum of a system. So, when momentum is being transferred from 1st ball to 7th, the barycenter of all the balls moves, but it moves very little as the seven balls have greater mass. Eventually all of the momentum is transferred to the final ball and it moves off. The time delay can be between the first ball touching and the last ball moving off.

Remember, the first ball does not directly interact with the last.

Not really.

Although my explanation is quite "lay", just think about it for a while it should sink in.