Re: F=ma

[Leigh Palmer <palmer@SFU.CA>]

> This 1/m (see below) is like conductivity=1/resistivity.
> To what extent is I=V/R a good analogy for a=F/m?

It makes more sense to me that way, and I also prefer
J = sigma E, where J and E are vector quantities, and
sigma need not be a scalar. Does anyone ever construct a
resistivity matrix? Maybe that is why - it doesn't seem
to be as, well, sensible!

It just seems to be a better syntactic order to put the
cause on the right-hand side (at least to a right-handed
male anglophone*). "The force is the product of mass and
acceleration" seems unlikely; "force is a product of
sweat and perseverence" makes a more natural order, and
more sense. "Acceleration is the product of force and
responsiveness" makes more sense to me, where
"responsiveness" is inversely proportional to inertia.

I am worrying that the presentation of equations which
will initially be parsed as sentences by our students
may affect their ability to grasp concepts. Should we
pay some attention to this (I believe utterly neglected)
question? Any PER folks out there who might know of some
relevant work? Dewey?

Leigh

*I am sensitive to the possible influences of culture
and sex** on perception of sensibility.

**I am intolerant of the vulgar use of the term "gender"
in this context. English is not inflected by gender and
gender *per se* should not be a problem in physics
taught in English. It may cause problems in other
languages, but at least I don't have to worry about it.