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## Homework Statement

I want to find this:

C magnetic field strength of magnets

C magnetic force on ferromagnetic object

C force vs. distance

C force vs. material thickness (shielding)

Various metal objects of varrying thickness's

I have a scale

I have two permanent magnets

Dimensions:

Height = 0.41cm = 0.0041m

Diameter = 1.8 cm = 0.018 m

Area = πr² = π(0.009m)²

Area = 2.5∊-4 m²

Volume = πr²(h)

Volume = 1.03∊-6 m³

Collected data =d =distance (mm)|mass=(g)

d0, 235g

d1, 122g

d2, 90g

d3, 64g

d4, 44g

d5, 28g

## Homework Equations

F={{\mu q_{m1} q_{m2}}\over{4\pi r^2}}

A is the area of each surface, in m2

H is their magnetizing field, in A/m

μ0 is the permeability of space, which equals 4π×10−7 T·m/A

B is the flux density, in T.

F=\frac{\mu_0 H^2 A}{2} = \frac{B^2 A}{2 \mu_0}

B0 is the magnetic flux density very close to each pole, in T,

A is the area of each pole, in m2,

L is the length of each magnet, in m,

R is the radius of each magnet, in m, and

x is the separation between the two magnets, in m.

F(x) = \frac{\pi\mu_0}{4} M^2 R^4 \left[\frac{1}{x^2} + \frac{1}{(x+2t)^2} - \frac{2}{(x + t)^2}\right]

B0 = μ0M

The effective magnetic dipole can be written as

m = MV

Where V is the volume of the magnet. For a cylinder, this is V = πR2t.

When t < < x, the point dipole approximation is obtained,

F(x) = \frac{3\pi\mu_0}{2} M^2 R^4 t^2\frac{1}{x^4} = \frac{3\mu_0}{2\pi} M^2 V^2\frac{1}{x^4} = \frac{3\mu_0}{2\pi} m_1 m_2\frac{1}{x^4}

I am thinking I may need to gather more data in order to find what I am looking for.

## The Attempt at a Solution

Force vs Distance graph has been done as for the others I am not sure what formulas to use or how to gather the information, from a permanent magnet.