Finding the restoring force, Hooke's Law

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Homework Help Overview

The problem involves Hooke's Law and the behavior of a spring under different loading conditions. It presents a scenario where a spring is stretched by a weight and later subjected to opposing forces.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the calculation of the spring constant and its implications for different scenarios. Questions arise regarding the net force when two individuals pull on the spring and whether the spring constant remains unchanged.

Discussion Status

Some participants have offered clarifications regarding the behavior of the spring under tension and the nature of the forces involved. There appears to be a productive exploration of the concepts, although no explicit consensus has been reached on the final interpretation of the restoring force.

Contextual Notes

Participants are considering the implications of pulling forces on the spring and the assumption that the spring constant remains constant throughout the discussion.

h8ligan
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Homework Statement



Hooke's law describes a certain light spring of unstretched length 35.0cm. When one end is attached to the top of a door frame and a 7.50kg object is hung from the other end, the length of the spring is 41.5cm. a) Find its spring constant. b)The load and spring are taken down. Two people pull in opposite directions on the ends of the spring, each with a force of 190N. Find the length of the spring in this situation.

Homework Equations



F=-kx

The Attempt at a Solution


I found the spring constant in a) and it was 1130N/m which I am unsure if it is the same for b. The real problem is I can't figure out how I am supposed to find the restoring force. My thoughts seem to think that because they are pulling in opposite directions at the same force then the net force would be zero and therefore so would the restoring force?
 
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Imagine pulling on a spring attached to a wall. Now imagine pulling on the spring in part B.
 
Ok so then it would stretch, and would be double? What about the spring constant would it remain the same?
 
h8ligan said:
Ok so then it would stretch, and would be double? What about the spring constant would it remain the same?

For the purposes of what we're doing, the spring constant is always constant.

If one pulls on a mounted spring, the spring has a force f=kx. If two people pull on the spring there are now two forces. f1+f2=kx.
 
Okay, thank you I believe I got it :)
 

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