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Q & A: Calculating Magnetic Force

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Most recent answer: 10/22/2007
Q:
How to calculate how much force is produced by a small 3cm-3cm-3.5cm rectangular magnet?
- Nicholas Rice (age 16)
Barstow High School, CA, USA
A:
Nicholas -

There are ways to calculate the force from a magnet, but you have to know more than just how big the magnet is. Most importantly, you need to know what it's made of - some magnetic materials create a stronger magnetic field than others. You also need to know what the other object is that feels the magnetic force. Another magnet would probably feel a stronger force than a sheet of steel, and a piece of plastic or aluminum would feel almost no force at all. The size and shape of the object also strongly affect the magnetic force on it. The easiest way to figure this out is to try using the magnet to lift various sized objects (of the same material). The weight (in pounds) of the heaviest object that you can lift using the magnet is the force that the magnet produces on it.

-Tamara

(published on 10/22/2007)

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