Work Done by Spring: Solving the Mystery

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Discussion Overview

The discussion revolves around the work done by a variable force on a spring, specifically addressing why the work done by an external force is not simply the product of the external force and the distance stretched. The scope includes conceptual understanding and mathematical reasoning related to spring mechanics.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Mathematical reasoning

Main Points Raised

  • Some participants note that the force exerted by the spring varies as a function of the distance stretched, which complicates the calculation of work done.
  • One participant describes the natural position of the spring as stable at x=0 and suggests that external forces lead to instability, prompting the spring to exert a counteracting force.
  • Another participant questions whether the increasing force required to stretch the spring is due to the nature of the spring's response to external forces.
  • A participant explains that when a constant external force is applied to a spring, the object attached to the spring will initially accelerate until the spring's force balances the external force, leading to a state of motion rather than rest.
  • One participant provides a link to an article for further mathematical insight into the topic.
  • Another participant expresses surprise at the lack of familiarity with Hooke's law in the context of the problem being discussed.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the relationship between force and distance in the context of spring mechanics. There is no consensus on a definitive explanation for the work done by the external force, and multiple viewpoints regarding the nature of the forces involved remain present.

Contextual Notes

Participants reference Hooke's law and the variable nature of spring force, but the discussion does not resolve the assumptions or mathematical steps necessary to fully understand the work done by the external force.

T-Hau
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I have been scratching my head on this problem and hope that someone might solve my problem.
The question is about work done by a variable force on a spring. When a spring is stretched x distance from its initial position by an external force.Why the work done by the external force is not equal to F(external) * x?
 
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T-Hau said:
I have been scratching my head on this problem and hope that someone might solve my problem.
The question is about work done by a variable force on a spring. When a spring is stretched x distance from its initial position by an external force.Why the work done by the external force is not equal to F(external) * x?

Because the force is a variable and varies as a function of x.

Zz.
 
suppose, the natural position (where no force is acting on the spring) is at x=0 (stable). It's obvious that it will not stretch unless some external force is applied. Let us say, the action of any external force will lead to instability. Now, the spring exerts a force against the external force to attain stability. So, more the instability, more the force the spring is going to exert...
 
ZapperZ said:
Because the force is a variable and varies as a function of x.

Zz.

What u meant by function of x?
 
AudioFlux said:
suppose, the natural position (where no force is acting on the spring) is at x=0 (stable). It's obvious that it will not stretch unless some external force is applied. Let us say, the action of any external force will lead to instability. Now, the spring exerts a force against the external force to attain stability. So, more the instability, more the force the spring is going to exert...

Is it because as the spring is stretched more, it takes more force to stretch it?
 
T-Hau said:
Is it because as the spring is stretched more, it takes more force to stretch it?

as the spring is stretched more, more force is exerted by the spring on the body applying the external force.

if you apply a continuous and unchanging force F on an object attached spring whose other end is fixed to a wall, the object will first accelerate, till the acceleration becomes 0 (due to the backward force exerted by the spring). When the acceleration becomes 0, the object is not at rest but at a certain velocity. Now, it will start decelerating till the object come to rest.
 

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T-Hau said:
Is it because as the spring is stretched more, it takes more force to stretch it?

Are you familiar with Hooke's law? I'm a bit puzzled that you are asked to solve a problem using springs, but this appears to be a surprise to you.

Zz.
 

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