Calculate force on Permanent Magnet near a Paramagnetic surface

In summary, the conversation discusses the creation of a sensor to detect paramagnetic materials. The setup involves a permanent disk magnet on a force sensor with an air gap between the sensor and the material. The question is whether the force can be calculated based on parameters such as magnetic field strength, radius of the magnet, height of the magnet, distance between the magnet and surface, and magnetic susceptibility of the surface. The person is not a physics major and is looking for help with the calculation. They have found a formula for magnetic flux density and believe that once they have this value, it will be easy to calculate the force.
  • #1
DeathCheese
2
0
Hello all, new here but plan to stick around for a while. I am currently trying to make a sensor that can detect if a material below it is paramagnetic. I believe paramagnetic is the proper term, but it needs to detect if the force exerted by permanent magnet is above a certain threshold. The setup is simple with a permanent disk magnet sitting on a force sensor with an air gap between the force sensor and the paramagnetic surface. Anyways, if I know the following parameters, can I calculate the force, or am I being naive?
  • Magnetic Field Strength (B)
  • Radius of magnet (r)
  • Height of magnet (h)
  • Distance between magnet and surface (d)
  • Magnetic Susceptibility of surface (X)
Not sure if it's important but I'm assuming the surface being detected has an infinite area due to its size compared to the permanent magnet and sensor.

I appreciate any and all help, note I'm not a physics major so this might not be as difficult as I am making it. Thanks in advance!
 
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  • #2
So I found the formula for magnetic flux density of a cylinder magnet. I guess once I find the flux density it should be pretty easy to find the force exerted. If I am missing anything let me know please.
 

1. How do you calculate the force on a permanent magnet near a paramagnetic surface?

The force on a permanent magnet near a paramagnetic surface can be calculated using the formula F = (μ_0 * m_1 * m_2 * V)/(4π * r^4), where F is the force, μ_0 is the permeability of free space, m_1 and m_2 are the magnetic moments of the magnet and the surface, V is the volume of the magnet, and r is the distance between the magnet and the surface.

2. What is the difference between a permanent magnet and a paramagnetic surface?

A permanent magnet is a material that has its own magnetic field and can retain its magnetization even when removed from an external magnetic field. A paramagnetic surface, on the other hand, is a material that becomes weakly magnetic when placed in an external magnetic field but loses its magnetism when the external field is removed.

3. How does the distance between the magnet and the surface affect the force?

The force between a permanent magnet and a paramagnetic surface is inversely proportional to the distance between them. This means that as the distance between the two decreases, the force increases, and vice versa.

4. Can the force on a permanent magnet near a paramagnetic surface be repulsive?

Yes, the force between a permanent magnet and a paramagnetic surface can be either attractive or repulsive. This depends on the orientation of the magnetic moments of the two objects. If they are aligned in the same direction, the force will be attractive, but if they are aligned in opposite directions, the force will be repulsive.

5. What are some real-life applications of calculating the force on a permanent magnet near a paramagnetic surface?

This calculation is important in the development of magnetic levitation systems, where a strong magnetic force is used to lift and suspend objects above a paramagnetic surface. It is also used in the design of magnetic bearings, which are used in high-speed machinery to reduce friction and increase efficiency. Additionally, this calculation is essential in the study of magnetic materials and their properties.

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