How Do Electric and Magnetic Forces Interact with Charges?

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Discussion Overview

The discussion revolves around the interaction of electric and magnetic forces with charges, particularly in the context of different frames of reference and the effects of acceleration on these forces. Participants explore hypothetical scenarios involving charges in a moving box and the implications of relative motion on observed forces.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant proposes a thought experiment involving two charges in a moving box, suggesting that an observer outside the box would measure a greater electric force due to acceleration, implying the existence of a magnetic force acting in the opposite direction.
  • Another participant questions the scenario by clarifying that the charges are floating and not in contact with the box, prompting a discussion about the effects of acceleration on the charges.
  • A further response indicates that the charges will only move relative to each other if there is a mutual attraction or repulsion, regardless of the box's motion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the implications of the thought experiment, and there are competing views regarding the behavior of the charges under acceleration.

Contextual Notes

The discussion lacks clarity on the assumptions regarding the nature of the charges and their interactions, as well as the specific definitions of forces involved. The effects of acceleration on the system remain unresolved.

kent davidge
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(sorry my bad english)
Let's imagine two frames of reference, one of which is a imaginary room containing two charges. Now let's accelerate this room from 0 to v and keep that speed during some time interval t and then we "pause" the situation again. An observer inside the box would measure the electric force acting on the charges and the observer in the other frame would measure a greater electric force. But the final positions of the two charges after time t should be the same as seen by all observers. So, there must be a force acting on the opposite direction as seen by the observer outside the room, that decreases the net force, and that force is what we call magnetic force.

Is it correct to think so?
 
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Assuming you mean the 2 charges are just floating in the box ...
(ie not in physical contact with the inner walls of the box)

now it doesn't have to be charges ... it could be 2 of anything
what do you think will happen to those 2 objects when you accelerate the box ?

Dave
 
davenn said:
Assuming you mean the 2 charges are just floating in the box ...
yes
davenn said:
what do you think will happen to those 2 objects when you accelerate the box ?
Okay. I just wanted to think of a box as being in one frame of reference, but let's forget it. Just think that the 2 charges start moving.
 
kent davidge said:
Just think that the 2 charges start moving.

I think you missed what I was trying to hint to you
They will only start moving relative to each other and the walls of the box if there is a mutual attraction or repulsion between them
That's even if the box isn't moving.
 
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davenn said:
I think you missed what I was trying to hint to you
:biggrin:
 

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