Magnetism: Where Does Energy Come From?

  • Context: Undergrad 
  • Thread starter Thread starter Hooloovoo
  • Start date Start date
  • Tags Tags
    Magnetism
Click For Summary
SUMMARY

The discussion centers on the energy dynamics involved when a magnet interacts with iron. When a magnet is placed near iron, the magnetic field exerts a force, converting potential energy into kinetic energy as the iron accelerates towards the magnet. This process does not violate energy conservation; rather, the potential energy of the magnetic field decreases as the iron gains kinetic energy. The interaction illustrates the fundamental principles of energy transfer within magnetic fields.

PREREQUISITES
  • Understanding of magnetic fields and forces
  • Basic knowledge of kinetic and potential energy
  • Familiarity with Newton's laws of motion
  • Concept of energy conservation in physics
NEXT STEPS
  • Research the principles of electromagnetic fields and their effects on nearby objects
  • Explore the relationship between potential energy and kinetic energy in different physical systems
  • Study the implications of energy conservation in magnetic interactions
  • Investigate real-world applications of magnetism in technology and engineering
USEFUL FOR

Students of physics, educators teaching magnetism, and professionals in engineering fields focused on electromagnetism and energy transfer.

Hooloovoo
Messages
30
Reaction score
0
I place a magnet near a piece of iron. The iron bit accelerates across the floor towards the magnet.

The magnet has done work. Energy has been expended. Where did this energy come from?

This energy seems inexhaustible. Why isn't it used up?
 
Physics news on Phys.org
The energy came from the magnetic field.

How is this any different from placing a massive object near a particle and watching the particle accelerate towards the large object, due to the gravitational attraction between them ?

The potential energy from the field is converted into kinetic energy. There's no violation of energy conservation.
 
Is the potential energy of the field therefore reduced, by being converted to kinetic energy?
 
Yes. The presence of the iron affects the magnetic field, in such a way that the total energy of the field decreases as the chunk of iron approaches the magnet and gains kinetic energy.
 

Similar threads

Undergrad How Does a Magnetic Repulsion Machine Work?
  • · Replies 5 ·
Replies
5
Views
2K
High School Permanent magnets and energy question
  • · Replies 16 ·
Replies
16
Views
3K
High School Experiment issues (electromagnetism)
  • · Replies 42 ·
2
Replies
42
Views
3K
Undergrad Charge movement relative to magnetic field frame dependence/invariance
  • · Replies 5 ·
Replies
5
Views
1K
High School Magnetic force driving a small iron ball
  • · Replies 4 ·
Replies
4
Views
2K
Graduate Work done by permanent magnets
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Where do magnets get their energy?
  • · Replies 18 ·
Replies
18
Views
3K
Undergrad Where does the energy come from? (magnet)
  • · Replies 12 ·
Replies
12
Views
17K
Graduate Conservation of Energy on Current-Carrying Wire in Magnetic Field
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Homopolar generator question: Magnetic “wake”
  • · Replies 7 ·
Replies
7
Views
3K