What makes work positive (electricity)

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SUMMARY

The discussion clarifies the concepts of positive and negative work in the context of electric charges. When three charges are brought together from infinity, the work done depends on the nature of the forces involved. If the charges are attractive, such as in gravitational forces, the work done is positive, resulting in negative potential energy. Conversely, if the charges are repulsive, the work done is negative, leading to positive potential energy. This distinction is crucial for understanding electrostatics and energy interactions.

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  • Understanding of electric charge interactions
  • Familiarity with potential energy concepts
  • Knowledge of conservative forces
  • Basic grasp of vector mathematics (force and displacement)
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  • Learn about conservative forces and their implications in physics
  • Explore the mathematical formulation of work done by forces
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Eats Dirt
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I don't really understand the concept of what makes work positive or negative for example if 3 charges are brought together from infinite what is the work done on them?

I am extremely confused about what make work positive and negative.
 
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Hi Eats Dirt! :smile:

Potential energy = minus the work done by a conservative force.

And work done = force "dot" displacement …

so if the charge is attractive (like gravity), the force is in the same direction as displacement, so the work done by the force is positive, and the potential energy difference is negative

but if the charge is repulsive, the force is in the opposite direction to displacement, so the work done by the force is negative, and the potential energy difference is positive :wink:​
 

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