A simple question about a magnet's force on a steel bar

[WarpedWatch]

Greetings,

I've been trying to teach myself about magnetic phenomena and I've recently been tinkering with a finite element package called quickfield (from quickfield.com).

I made a model of a simple permanent magnet with one of the magnet's poles facing a steel bar. The software has a method that allows me to click on the steel bar and calculate the force that the steel bar is experiencing. The map of the resulting B field seems to make sense to me but the resulting forces have me puzzled. For example, if the steel bar is pressed directly against the pole of the magnet, the software shows that the steel is experiencing a force that is less than if the steel bar is slightly removed from the surface of the magnet. Should this be the case? In real life, does having the steel pulled slightly away from the magnet actually cause the steel to experience greater pull than if the steel were in direct contact with the magnet's pole? Or might this be some oddball artifact of the software or my model?

Many thanks for your insights here. :-)

 

[eljose79]

Thank you for your interest in magnetic phenomena and for sharing your experience with the quickfield software. As a scientist who specializes in electromagnetism, I would like to offer some insights on your question about the forces experienced by the steel bar in your model.

Firstly, it is important to note that the magnetic force between two objects is dependent on the distance between them. As the steel bar is pulled away from the magnet's pole, the distance between them increases and therefore the force decreases. This is known as the inverse square law of magnetism, which states that the force between two magnetic objects is inversely proportional to the square of the distance between them.

In real life, this means that the steel bar will experience a greater force when it is in direct contact with the magnet's pole compared to when it is slightly removed from it. This is because the magnetic field is strongest at the surface of the magnet, and the force between the two objects is directly related to the strength of the magnetic field.

As for your observation in the software, it is possible that it is accurately depicting the forces based on your model and the parameters you have set. However, it is always important to cross-check with real-life experiments to validate the results obtained from simulations.

I hope this helps to clarify your doubts. Keep exploring and learning about magnetic phenomena, and don't hesitate to ask for further clarification or assistance. Good luck with your studies!