Why are electromagnetic forces body/volume forces?

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    Electromagnetic Forces
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Discussion Overview

The discussion revolves around the classification of electromagnetic forces as body or volume forces, particularly in comparison to gravitational forces. Participants explore the implications of these definitions and the effects of forces on different particles, including electrons, protons, and neutrons.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions the definition of volume forces, suggesting that electromagnetic forces may not fit this classification due to their selective effects on particles like electrons and protons, while neutrons are unaffected.
  • Another participant argues that the electromagnetic force is still considered a volume force because it acts throughout the entire volume of the material, even if it affects different particles differently.
  • A participant expresses confusion about the implications of gravitational force, noting that all mass is affected equally by gravity, which contrasts with the selective nature of electromagnetic forces.
  • There is a discussion about the acceleration of protons and electrons under gravity, with a clarification that while the force on protons is greater due to their mass, both experience the same acceleration in a gravitational field.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the classification of electromagnetic forces as volume forces. There are competing views regarding the implications of particle interactions and the definitions of forces.

Contextual Notes

Participants express uncertainty about the definitions of volume forces and how they apply to different particles, highlighting potential ambiguities in the definitions they encountered.

Logerah
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Hi,

I don't really get what the point of volume forces is, if electromagnetism is a volume force. Its obviously no surface force, but in my opinion the definition says that its no volume force as well. The link below describes volume forces as "a force acting on all particles (volume elements) of a given body and proportional to the mass of the particles. Gravitationalforce is an example of a volume force.".
But electromagnetic force doesn't affect neutrons. They also affect some particles more than others: electrons and protons have different mass and especially different charge.
Gravity is different. Every bit of mass is affected equally?!
Every source I found says its a body force so my thoughts must be wrong. Does anyone see where my mistake is?

http://encyclopedia2.thefreedictionary.com/Volume+Force
 
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Logerah said:
But electromagnetic force doesn't affect neutrons.
That does not matter. Its effects are in the whole volume, not limited to the surface. An interaction that would only affect electrons would still be called "volume force" if it would act on all electrons in the material.

Logerah said:
Every bit of mass is affected equally?!
With the same argument as you used for the charge, you could say "protons are heavier, they are affected more by gravity".
 
Ok, thank you.. So I think the definitions I read are a bit misleading.
mfb said:
With the same argument as you used for the charge, you could say "protons are heavier, they are affected more by gravity".
Protons should fall with 9,81m/s² and electrons, too. So they actually get affected the same... Or am I mistaken? Are the protons of a body on Earth pulled down more? That doesn't really make sense to me...
 
Logerah said:
Protons should fall with 9,81m/s² and electrons, too. So they actually get affected the same...
Depends on what you call "the same" - same force or same acceleration?
For protons the force is larger. The acceleration is the same for both of course.
 

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