Is there traction force between moving electrons & copper wire?

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SUMMARY

The discussion centers on the concept of traction force between moving electrons and copper wire in electrical circuits. Participants argue that while there may be a momentary force as current ramps up or down, in a steady state, the forces exerted by electron collisions and scattering events cancel out, resulting in no net force. The analogy of a mouse running on a ring track is used to illustrate the concept of forces in a closed circuit. Ultimately, the consensus is that the term "traction" is not appropriate for describing the interactions between electrons and the atomic structure of the conductor.

PREREQUISITES
  • Understanding of basic electrical concepts, including current and resistance.
  • Familiarity with Newton's laws of motion, particularly action and reaction forces.
  • Knowledge of electron behavior in conductive materials.
  • Basic principles of electromagnetic fields and forces.
NEXT STEPS
  • Explore the concept of electron mobility in conductors and its impact on resistance.
  • Learn about the role of electromagnetic fields in electrical circuits.
  • Investigate the behavior of electrons in different materials, including superconductors.
  • Study the principles of Newton's laws as they apply to electrical systems and forces.
USEFUL FOR

Physicists, electrical engineers, and students studying electromagnetism or materials science will benefit from this discussion, particularly those interested in the interactions between electrons and conductive materials.

cairoliu
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Common sense: walking on road, there is traction between shoes & earth.
I'm wondering: same thing for electric current's electrons & copper wire?
 
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If it's true, then if million DC amps flowing, then there may be recoil back force sensed by conducting wire.
 
I don't think so, and even if there is the force is going to be exerted all along a closed loop, so the recoil would cancel out to zero net force.
 
Drakkith said:
I don't think so, and even if there is the force is going to be exerted all along a closed loop, so the recoil would cancel out to zero net force.
Imaging a mouse running in-cage ring track.

fun-for-the-whole-family.gif


The recoil force spins the wheel of ring track, no cancellation of recoil to zero?

The ring track is analog to a closed circuit.

The running mouse seems to be always around bottom of cage, because the ring track is light very much, so little the friction on axle, in comparison to mouse weight.

If customizing a bigger friction ring track, it's possible to see mouse climbing near the top of cage.

In nuclear physics experiment, there is a so-called Theta Pinch, which carries millions amps, but unfortunately the 2 terminals are fastened to base frame; if not, I guess the copper coil may be seen spin? Not sure anyway.
 
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cairoliu said:
he recoil force spins the wheel of ring track, no cancellation of recoil to zero?

The ring track is analog to a closed circuit.
Ah, I see what you mean. I didn't take possible rotation into account. There might be a small force as the current ramps up and as it ramps down, but in the steady state there won't be a net force, as the force from the collisions and scattering events between the electrons and the ions would cancel out the accelerating force on the electrons.

Perhaps an isolated circuit might temporarily spin itself around slowly if floating in a vacuum, like a small motor turning a larger ring could do. I'm honestly not sure.
 
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I think the force you mention is caused by the resistance of the metal. Electrons are not entirely free to move in a metal but require small force to do so. When we apply an EMF across the ends of a conductor, the electrons feel a force in one direction and the atoms feel a force in the other direction. However, the atoms are locked into the metallic structure and cannot move. The force felt by the atoms may be considered to be the reaction force.
The definition of Newton's action and reaction is just a matter of which is the desired force.
 
"Traction" is probably not the word you want.

If I apply an electric field to a wire, the electrons feel a force F in one direction, and the nuclei a force -F in the same direction. (Also, the electrons eventually arrange themselves so that there is no force on either)
 

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