Magnetic pull force with a gap

[isaacc]

Hello. I'm a cabinetmaker and my college physics courses are 25 years behind me now. I'd consider it a kindness if someone would answer a question for me regarding magnetism.

I have a magnetic strip that is described as having 6.2 lb. of magnetic pull force per lineal foot, 1" wide and 0.020" thick, and at 0" of air gap.

How would I recalculate that for a gap of about 1/8" through a transparent material such as lexan?

I'm hoping it's as simple as applying some co-efficient or simple calculation based on the gap distance.

Thank you.

 

[elegysix]

there isn't a simple way to do it, you'll just need to measure the force for a single foot of the material with the spacing. Even then it will only be an approximation. the force for a single foot will be the force per foot you're looking for.

 

[mfb]

I think I would try to determine it in experiment. While it is possible to calculate it with some additional assumptions about the magnetism in the strip, I think that the corresponding errors would be quite large.

Edit: Nice timing.