Uniform Electrical potential energy

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Discussion Overview

The discussion revolves around the concept of how potential energy behaves in a uniform electric field, particularly focusing on the mathematical representation of potential energy changes as a point charge moves from higher to lower potential energy. Participants explore the relationship between potential energy, kinetic energy, and the forces involved in this process.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant seeks clarification on how potential energy decreases as a charge moves in an electric field, questioning the mathematical representation of this process.
  • Another participant points out that the change in position (delta X) is negative when considering movement towards lower potential energy.
  • A different perspective introduces the concept of work done by a conservative force, explaining that while the force acts in the direction of decreasing potential energy, the particle may not necessarily move in that direction if given an initial velocity opposing the force.
  • One participant challenges the notion of potential energy "traveling," suggesting that it is the system or object that changes to reduce potential energy rather than the energy itself moving.
  • Another participant agrees with this perspective, emphasizing that it is the particle that accelerates towards lower potential energy, not the potential energy itself that moves.

Areas of Agreement / Disagreement

Participants express differing views on the conceptualization of potential energy movement, with some arguing that potential energy does not move while others attempt to clarify how energy changes occur during particle motion. The discussion remains unresolved regarding the interpretation of potential energy in this context.

Contextual Notes

There are limitations in the discussion regarding the definitions of potential energy and the assumptions about motion and forces involved. The mathematical steps and relationships between force, work, and potential energy are not fully resolved.

ysmin55555
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Can someone explain the math of how potential energy travels from higher potential energy to lower potential energy (PE) along a uniform electric field?

I understand that in order for the point charge to move, gaining kinetic energy, it will lose potential energy. But using the equation PE=qdeltaXE, Q is positive, delta X is position and E is positive. So what am I missing to quantitatively show that potential energy is decreasing?
 
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ysmin55555 said:
delta X is position
##\Delta x## is change in position, which is negative in your example.
 
Your question can be more general. In one dimension:
the work done is dW = F Δx.
If the force is conservative, the potential energy is defined as ΔU = - ΔW = - F Δx
The force is F = - ΔU/Δx
So the force is in the direction of decreasing potential energy. That only says that the acceleration is in the direction of decreasing potential energy, not that the particle moves in the direction of decreasing potential energy. For example, the particle could be given an initial velocity in the direction of increasing potential energy (you could throw a ball up), and it would slow down because the force is opposite to the direction of motion.
The electrostatic force is a particular example of this, with F = qE.
 
ysmin55555 said:
how potential energy travels from higher potential energy to lower potential energy
That's not the way to discuss energy, imo. A system / object may move m(or just change) in such a way as to reduce the Potential Energy but the PE hasn't actually moved. A possible exception to that statement could be throwing a coiled spring across a room. In that case you could say that the PE of the coiled spring has moved but I don't think that would take you anywhere useful.
 
There was that problem in the language of ysmin55555. As sophiecentaur says, the potential energy does not move anywhere. It is the particle that accelerates towards lower potential energy.
 

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