Initial Tension Of Parallel Spring System

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Homework Help Overview

The discussion revolves around calculating the initial tension or pretension in a system of two parallel springs, given specific values for force, spring constants, and displacement. The context involves understanding how these parameters interact in the system.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants explore the relationship between total force, spring constants, and initial tension. There are attempts to clarify the definitions and terms used, particularly regarding "pretension." Some participants suggest different formulations for expressing initial tension based on the system's configuration.

Discussion Status

The discussion is active, with participants providing various interpretations and approaches to the problem. Some guidance has been offered regarding how to express the initial tension, and there is an ongoing exploration of the correct relationships between the variables involved.

Contextual Notes

There are questions about the terminology used, specifically the term "pretension," and requests for additional clarification, such as diagrams or restatements of the problem. The original poster's expectations regarding the initial tension value are also noted, indicating a potential misunderstanding or miscalculation that is being examined.

stannard97
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Homework Statement


How to calculate initial tension or pretension in a system of two parallel springs.
F=5.33213N
K1+K2=53.0597
x=0.095

Individual springs have initial tension of 0.25N so I would expect an answer of 0.5N but I can't get there.

Homework Equations


F=(k1+k2)x

The Attempt at a Solution


Total force applied - Initial tension = (k1+k2)x
Total force applied - (k1+k2)x = Initial tension = 0.29?
 
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Could you please restate the problem exactly as it reads? And provide a drawing perhaps? Also, I have never seen the word pretension used that way. Ever.
 
Those pretentious springs! Such over-inflated senses of self-worth!
 
AlephNumbers said:
Could you please restate the problem exactly as it reads? And provide a drawing perhaps? Also, I have never seen the word pretension used that way. Ever.
Calculate the initial tension of two springs in parallel by treating them as a single spring. Initial tension as in the force needed to begin extending the spring. Ktotal is the sum of individual spring constants and total force is shared between both springs.
 

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I would say that (k1 + k2)x - F = initial spring tension, not F - (k1 + k2)x.
 
Think about the initial state of the springs. The tension in them can be expressed as (k1 + k2)[x][/0] and then the force F further stretches the springs to the value (k1 + k2)x. Thus, (k1 - k2)x - F = initial tension.
 
AlephNumbers said:
I would say that (k1 + k2)x - F = initial spring tension, not F - (k1 + k2)x.
But Fafter equilibrium=ktotal*x
where Ftotal is F required to overcome initial tension+Fafter equilibrium
so Ftotal-Initial Tension=ktotal*x
 
Yeah that looks good. Thank you for clearly and concisely representing the quantities.
 

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