Unanswered Question: Who Does Mechanical Work for Magnetism?

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SUMMARY

The discussion centers on the mechanical work associated with magnetic forces, specifically the Lorentz forces that do not perform mechanical work. It is established that when a magnetic dipole with a magnetic moment \(\vec{\mu}\) is placed in a non-uniform magnetic field \(\vec{B}\), it experiences a force \(\vec{F} = -\vec{\nabla}E\), where energy \(E = -\vec{\mu} \cdot \vec{B}\). The movement of the dipole towards regions of lower energy is described as virtual work, confirming the relationship between magnetic fields and mechanical work.

PREREQUISITES
  • Understanding of Lorentz forces and their implications in magnetism
  • Familiarity with magnetic dipoles and magnetic moments
  • Knowledge of energy concepts in magnetic fields
  • Basic principles of vector calculus, particularly gradients
NEXT STEPS
  • Study the principles of magnetic dipoles in non-uniform magnetic fields
  • Explore the concept of virtual work in physics
  • Learn about the applications of the gradient operator in electromagnetism
  • Investigate the relationship between kinetic energy and magnetic forces
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This discussion is beneficial for physicists, electrical engineers, and students studying electromagnetism, particularly those interested in the mechanics of magnetic forces and energy transformations in magnetic fields.

Frank66
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May be a trivial question...
The forces that arise from the magnetic field are Lorentz forces that not make mechanical work.
When a piece of iron is attracted by a magnet is accelerated and its kinetic energy increases: Who does the work necessary?
 
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I'm not sure about my answer, that's why I will formulate it in a question:
when a magnetic dipole with a magnetic moment \vec{\mu} is in a magnetic field \vec{B}, it has an energy E= -\vec{\mu}.\vec{B}. Now if \vec{B} is not uniform, there will be regions in space where the energy of the dipole is lower than in other regions and the dipole will move to that places, we call it virtual work, is that right?
The force exerted on the magnet dipole is \vec{F} = -\vec{\nabla}E, true?
 

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