Total tension in wire due to bird

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Homework Help Overview

The discussion revolves around a conceptual question regarding the tension in a wire due to a bird resting on it. Participants are examining the relationship between the calculated tension and the interpretation of "total tension" versus "tension" in the wire.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the calculation of total tension and its interpretation, particularly whether the total tension should be considered as the sum of tensions on either side of the bird or as a singular value. There are inquiries about the implications of the bird's position on the wire and how it affects tension.

Discussion Status

Some participants have offered clarifications regarding the terminology used, distinguishing between "total tension" and "tension" in the wire. There is an ongoing exploration of how the bird's position might affect the tension in the wire, with references to the assumptions made in the original problem setup.

Contextual Notes

There is mention of a specific problem context that involves a bird on a wire, and the discussion includes references to previous threads for additional context. The term "total tension" appears to be a point of confusion, as it is not explicitly defined in the original question.

Subdot
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Homework Statement


I have a conceptual question related to the exact problem in this thread: https://www.physicsforums.com/showthread.php?t=125801


Homework Equations



Same as in this thread: https://www.physicsforums.com/showthread.php?t=125801

The Attempt at a Solution



My question is why is the total tension 613 N? If you try and solve T1 = 9.81/(2sin(tan-1(0.200/25.0))), you get T1 = 613 N. However, T1 = T2. So wouldn't the total tension in the wire be 1,230 N (after rounding due to significant figures)? Could someone please explain this to me?
 
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Subdot said:
My question is why is the total tension 613 N? If you try and solve T1 = 9.81/(2sin(tan-1(0.200/25.0))), you get T1 = 613 N. However, T1 = T2. So wouldn't the total tension in the wire be 1,230 N ?

Hi Subdot! :wink:

The question asked "How much tension does the bird produce in the wire?" …

on the left, there is 613 N, and on the right there is 613 N …

so the tension in the wire is 613 N. :smile:
 
Hi! And so if I understand you right, "total tension" (which would be the total force the wire exerted on the bird, I guess) is not the same as just plain "tension" in a wire?

Out of curiosity, what would happen if the bird was not in the middle of the wire? How would you determine the amount of tension the bird causes in the wire then? Or would the tensions on either side of the bird still be the same?
 
Subdot said:
Hi! And so if I understand you right, "total tension" (which would be the total force the wire exerted on the bird, I guess) is not the same as just plain "tension" in a wire?

I've never heard of "total tension" …

it's not in the original question …

where did you get it from?​
Out of curiosity, what would happen if the bird was not in the middle of the wire? How would you determine the amount of tension the bird causes in the wire then? Or would the tensions on either side of the bird still be the same?

Tension in a continuous rope is the same all the way along.

Where it touches something, the tensions will still be the same on both sides provided there's no sideways force at that point, which in practice means no friction.

For example, most exam questions talk of "frictionless pulleys", because then the tension will be the same on each side of the pulley.

In the case of the bird, I think a lot depends on exactly how the bird attaches itself to the rope: that's why the question put the bird exactly half-way, so that it didn't matter. :wink:
 
Oh, I get it now. Thanks for the help! And "total tension" is a word I threw in there meaning the equivalent of "total force" acting on the bird from the wire. I probably got the word from the process of solving another problem involving tension.
 

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