Question

What's the relationship between a magnet's pull and repel force? Example: if a neodymium magnet's pull force is 75 pounds, what is the repel force? Explain thoroughly how you came up with your answer using a physics concept or equation.

Answer 1

The classical formula for the force between two magnetic poles is given by:

where the q's are the magnitude of the magnetic poles, measured in ampere-meter and r is the separation between the magnets.

You can easily see that the force only changes by a sign if you flip one of the magnets i.e, if they both were north-north , you get a repulsive force (+ve sign) and if both were south-south, it is still positive sign (repulsive still) but if one is north and other is south, there is only one -ve sign and there is an attractive force.

Either way, you can see that the magnitude does not depend on whether it is repulsive or attractive.