1
$\begingroup$

I'm here asking this as a student. Magnetic force can be effected by distance, the longer the distance, the weaker, the shorter the stronger. But does mass also effect magnetic force? Does a heavier magnet produce stronger magnetic force, compare to lighter one. when they're measured in the same distance? If so, is there an equation or formula to calculate it, the strength of the magnetic force? I've been looking for calculation formulas about magnetic forces for magnets on google, but I can't find anything about how mass affects magnetic force for a magnet. (Maybe I'm just using the wrong key word.)
Ps: This has nothing to do about electromagnetism, just normal magnets.

$\endgroup$

2 Answers 2

1
$\begingroup$

All permanent magnets have approximately the same density, the density of iron, because they mostly consist of iron or cobalt. Their maximum magnetization is also about the same, about two tesla (lower for ferrites).

The difference between materials of permanent magnets is their coercivity, their ability to keep their magnetization against demagnetizing fields. That is where Nd$_2$Fe$_{14}$B is better than AlNiCo-magnets. So Nd-magnets make it possible to produce more compact electrical motors (for car windows, power steering etc), where one would otherwise have needed large clunky AlNiCo magnets. (But AlNiCo is cheaper.)

That is why in practice, smaller magnets are stronger.

$\endgroup$
0
$\begingroup$

The simple answer is no, mass does not affect electromagnetic forces: only the position and movement of charges do.

See the Lorentz force $\mathbf{F} = q\left(\mathbf{E} + \mathbf{v}\times\mathbf{B}\right)$. Note that mass is nowhere to be found in this equation.

But what produces the $\mathbf{E}$ and $\mathbf{B}$, you may ask? Well, those can be determined from the position and movement of charges. (Search up Maxwell's equations.)

However, I should note that the mass of a charged particle does affect how it accelerates in response to the electromagnetic forces it feels. (If it's more massive, it will accelerate less.) Therefore mass is an important factor in calculating the future positions and velocities of the charges, and thus you cannot neglect the mass of the particles when understanding how the electromagnetic fields evolve over time.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.