Magnet on Metal Wall: Exploring the Work of Magnetic Fields

  • Thread starter Crazymechanic
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In summary, magnets can only do work if they are placed in a certain way and they need a power source.
  • #1
Crazymechanic
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Hi

a simple question that struck my mind.Let's imagine a ferrite magnet from a old loudspeaker now let's put that magnet on a metal wall , or door , the magnet holds to the metal vertically and any other material put similar would just fall off so t seems to me that the magnet or the magnetic field is doing work.
So is this true that the magnetic field is doing work or is it wrong , is the magnet just arranging elementary particles in such a way that let's those two physical objects attract each other like opposite charges attract one another?

Tahnks.
 
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  • #2
Hi Crazymechanic! :smile:

If I hang my hat on a peg on the wall, the peg stops the hat falling, but the peg does no work. :wink:
 
  • #3
Work = force * distance

Where's the distance?
 
  • #4
Hmm interesting answers.Ok Russ I let's assume we have a 5cm thick magnet and 5cm thick metal door, let's put a 1cm thick plastic material between the metal door and the magnet is now the magnet doing work? because the magnet is still holding on but at a distance away..?
 
  • #5
No: That's force applied at a distance, not through a distance. The "distance" in the work equation is the distance the object moved.
 
  • #6
"through a distance" aka "displacement".

Compare a fridge magnet to a book shelf. Neither is moving (zero displacement). Neither is doing any work to hold itself up. Neither needs a power source.
 
  • #7
This is a very important concept in physics...

If you hold a heavy book out at arms length (constant height) your body is doing no work on the book because the book is not moving. It doesn't feel like that because of the way the body works - it's is a biological machine. Were it a machine made of say metal or wood no power would be required to hold it still at a constant height (such a machine is called a bookshelf).

Large numbers of people missunderstand this issue. As a result they think magnets are a potential source of energy and try to build perpetual motion machines from them. They are wrong.
 
  • #8
CWatters said:
Large numbers of people missunderstand this issue. As a result they think magnets are a potential source of energy and try to build perpetual motion machines from them. They are wrong.

Or Gyroscopes.
Gyros are very popular with the loony fringe.
Gyros AND magnets now... :D
 

1. How do magnets work?

Magnets work by creating a magnetic field, which is a force that attracts or repels certain materials, such as metal. The magnetic field is created by the alignment of tiny magnetic particles within the magnet.

2. Why do magnets stick to metal?

Magnets stick to metal because metal is made up of atoms that contain electrons. These electrons are affected by the magnetic field of the magnet, causing them to align and create a force that attracts the magnet to the metal.

3. Can magnets lose their magnetism?

Yes, magnets can lose their magnetism over time. This can happen if the magnet is exposed to high temperatures, strong magnetic fields, or is dropped or struck with force. However, some magnets, such as neodymium magnets, are able to retain their magnetism for a longer period of time.

4. How can I make a magnet stick to a non-metallic surface?

In order for a magnet to stick to a non-metallic surface, the surface must contain magnetic particles, such as iron oxide. You can also make a non-metallic surface magnetic by rubbing a strong magnet against it in the same direction multiple times.

5. What are some practical applications of magnets?

Magnets have many practical applications, including use in motors, generators, speakers, and hard drives. They are also used in medical equipment, such as MRI machines, and in everyday items like refrigerator magnets and magnetic clasps on clothing.

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