Unanswered Question: Who Does Mechanical Work for Magnetism?

In summary, the conversation discusses the forces that arise from a magnetic field, specifically the Lorentz forces, and how they do not directly create mechanical work. The conversation also delves into the concept of magnetic dipoles and their energy in a magnetic field, as well as the force exerted on them. The question is posed as to who does the necessary work in this scenario and whether the force exerted on the dipole is true.
  • #1
Frank66
11
0
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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  • #2
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 [tex]\vec{\mu}[/tex] is in a magnetic field [tex]\vec{B}[/tex], it has an energy [tex]E= -\vec{\mu}.\vec{B}[/tex]. Now if [tex]\vec{B}[/tex] 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 [tex]\vec{F} = -\vec{\nabla}E[/tex], true?
 
  • #3


The work done in this scenario is done by the magnetic field itself. The magnetic field exerts a force on the iron, causing it to move and gain kinetic energy. This work is done by the magnetic field through the Lorentz forces acting on the iron. So, in a way, the magnet is doing the work by exerting a force on the iron. However, it is important to note that this work is not considered mechanical work as it is not caused by a physical displacement of the object, but rather by the force exerted on it. This concept can be further explored through the principles of electromagnetism and the relationship between electricity and magnetism.
 

FAQ: Unanswered Question: Who Does Mechanical Work for Magnetism?

What is mechanical work for magnetism?

Mechanical work for magnetism refers to the force exerted on a magnet or magnetic object by a mechanical source, such as another magnet or an electric current, resulting in movement or displacement of the object.

How is mechanical work for magnetism calculated?

The amount of mechanical work for magnetism can be calculated using the formula W = F x d, where W is the work done, F is the force exerted, and d is the distance over which the force is applied.

What is the significance of mechanical work for magnetism?

Mechanical work for magnetism is important because it helps to explain the relationship between magnets and mechanical forces. It also plays a crucial role in various technologies, such as electric motors and generators.

Who does mechanical work for magnetism?

Mechanical work for magnetism is done by the source of the mechanical force, such as another magnet or an electric current. It is not done by the magnet itself, as magnets do not possess the ability to do mechanical work.

Can mechanical work for magnetism be negative?

Yes, mechanical work for magnetism can be negative if the force and displacement are in opposite directions. This means that the mechanical force is working against the magnetic force, resulting in a decrease in mechanical energy.

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