Is there traction force between moving electrons & copper wire?

In summary, common sense says that there is traction between shoes and the earth, and the same thing might be true for electric current's electrons and copper 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.
  • #1
51
3
Common sense: walking on road, there is traction between shoes & earth.
I'm wondering: same thing for electric current's electrons & copper wire?
 
Physics news on Phys.org
  • #2
If it's true, then if million DC amps flowing, then there may be recoil back force sensed by conducting wire.
 
  • #3
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.
 
  • #4
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.
 
  • Like
Likes vanhees71
  • #5
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.
 
  • Like
Likes vanhees71
  • #6
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.
 
  • #7
"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)
 

Suggested for: Is there traction force between moving electrons & copper wire?

Replies
5
Views
2K
Replies
59
Views
4K
Replies
5
Views
784
Replies
4
Views
1K
Replies
1
Views
2K
Back
Top