The strength of magnetic force varies inversely with the square of the distance between the magnets. In other words,(adsbygoogle = window.adsbygoogle || []).push({});

Force = k/(distance^2)

Suppose that when two magnets are 4 cm apart, there is a force of 4 newtons. Find the work required to move the magnets from a distance of 3 cm apart to a distance of 11 cm apart.

4N = k/(0.04[tex]^{2}[/tex])m

4N = k/(0.0016m)

k = 2500

One thing that's thrown me for a loop though, is...

The distance between the magnets is 4 CM, or 0.04M.

So do I take the square of 4 CM to get 16 CM, or .16M.

Or do I square 0.04M to get 0.0016M, or .16CM.

I think it's the latter, but I'm not totally sure and I don't get second chances on this question.

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# Homework Help: Work/force with a magnet problem

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