To calculate work done from a graph

  • Context: Undergrad 
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    Graph Work Work done
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Discussion Overview

The discussion revolves around understanding why the work done is considered negative in a specific scenario involving a graph of force versus displacement. Participants explore the relationship between force and displacement directions and how they affect the calculation of work done.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions why the work done is negative, noting that displacement is in the positive x direction while the force appears to act in the negative x direction.
  • Another participant clarifies that the force is negative in that region, indicating it points opposite to the displacement.
  • A participant suggests that the increasing value of force in the negative region does not affect the sign of the work done, as it is the direction of force relative to displacement that matters.
  • There is a reiteration that as long as force and displacement are in opposite directions, the work done will be negative.
  • One participant expresses relief at the simplicity of the concept after the clarification.

Areas of Agreement / Disagreement

Participants generally agree on the principle that work done is negative when force and displacement are in opposite directions, though there is some confusion regarding the implications of force magnitude in the negative region.

Contextual Notes

Some assumptions about the definitions of force and displacement may not be fully articulated, and the discussion does not resolve the nuances of how force magnitude influences the understanding of work done.

esha
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In the given question part (a) I don't understand why the work done is negative? The answer says that the displacement is along positive x direction (i understand that) while force acting on the particle is along negative x direction ( why is that? since it appears that as the value of x is increasing so is the value of force. )
 
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esha said:
while force acting on the particle is along negative x direction
The value of the force is negative in that region, thus it points opposite to the displacement.
 
So it means that it doesn't matter doesn't matter whether the force is increasing or not in the negative region the force is increasing or not in the negative region
 
esha said:
So it means that it doesn't matter doesn't matter whether the force is increasing or not in the negative region the force is increasing or not in the negative region
Right. As long as the force and displacement are in opposite directions, the work done by the force will be negative.
 
oh... ok... its so fairly simple then
 

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