Does the proximity of a string to a spinning object affect its speed?

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Discussion Overview

The discussion revolves around the effects of a string's proximity to a spinning object on its speed, exploring concepts of rotational mechanics and angular velocity. Participants engage with both practical and philosophical implications of the question, considering scenarios involving high speeds and the nature of observation in physics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants assert that the string closer to the hand moves faster because it travels a larger circle in the same time frame.
  • Others argue that the string tied to the stone moves faster, as the angular velocity remains constant across the string.
  • A participant introduces a hypothetical scenario involving the stone moving at the speed of light, prompting further speculation about the implications of such speeds.
  • There is mention of a mathematical relationship concerning angular speed and the arc length traced by points on the string, suggesting that a point closer to the hand does not have a higher angular speed than the point at the rock.
  • Philosophical implications of observation and time flow are raised, questioning whether moving faster than light could affect the perception of time.

Areas of Agreement / Disagreement

Participants express conflicting views regarding the speed of the string segments, with no consensus reached on which segment moves faster. The discussion includes both practical mechanics and speculative philosophical questions, indicating a lack of resolution on the core question.

Contextual Notes

Participants reference basic principles of rotational mechanics, but there are unresolved assumptions regarding the implications of extreme speeds and the nature of time, which remain open for further exploration.

liongoth
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I wonder, if you tie a string to a stone and spin it around, does the string that is closer to your hand move faster than the string that is tied to the stone?

*EDIT* This question leads to a much greater topic of discussion, and the reason for leading off with this question is because the rest of the question is contingent upon this concept...
 
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Yes it does, since it has to travel a circle of larger diameter in the same amount of time.
 
liongoth said:
I wonder, if you tie a string to a stone and spin it around, does the string that is closer to your hand move faster than the string that is tied to the stone?
I'd say just the opposite.
 
liongoth said:
I wonder, if you tie a string to a stone and spin it around, does the string that is closer to your hand move faster than the string that is tied to the stone?

*EDIT* This question leads to a much greater topic of discussion, and the reason for leading off with this question is because the rest of the question is contingent upon this concept...

Hi and welcome to PF liongoth,

What kind of discussion are you fishing for here? The philosophical implications of basic rotational mechanics? I do not see your motive/s...
 
I think the string that is away moves faster. The radius is more but the angular velocity remains the same.
 
gendou2 said:
Yes it does, since it has to travel a circle of larger diameter in the same amount of time.

Aha, then if this is true, then what if the stone is moving at the speed of light?
 
See Doc Al's post.
 
Kurdt said:
See Doc Al's post.
What's the name of it, or a link for it?
 
liongoth said:
What's the name of it, or a link for it?

No, no, he means the earlier post made by Doc Al.

There is a basic mathematical relation to the angular speed of a given point on the string, and the length of the arc traced by that point. A point on the string closer to your hand would not have a higher Angular speed than the point at the rock. Not the other way around.

Check this page out for a basic tutorial on rotational mechanics: http://www.sparknotes.com/testprep/books/sat2/physics/chapter10.rhtml"
That should clear it up for you.

So, was there a philosophical question that you had?
 
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  • #10
Well, it was a matter of what really occurs when you observe the string, you see the string move so fast it goes backwards, and the thought had occurred to me that maybe we can move so fast that time will flow backwards, that is, if we could move faster than the speed of light...
 
  • #11
liongoth said:
Well, it was a matter of what really occurs when you observe the string, you see the string move so fast it goes backwards, and the thought had occurred to me that maybe we can move so fast that time will flow backwards, that is, if we could move faster than the speed of light...

Heh, no.
 
  • #12
liongoth said:
Well, it was a matter of what really occurs when you observe the string, you see the string move so fast it goes backwards, and the thought had occurred to me that maybe we can move so fast that time will flow backwards, that is, if we could move faster than the speed of light...

Nonsensical comments are not permitted at PF, even in the Philosophy forum. If you have a genuine question on the physics, then please post it in the relativity forum, otherwise, refrain from making the speculative posts in future.
 

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