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Re: when to write radians



--- Robert Cohen <Robert.Cohen@PO-BOX.ESU.EDU> wrote
in part:
If we want to be picky, all numerical ratios, while
dimensionless, st=
ill
have units.

I don't think it's being picky. We use radian measure
all the time; it would be nice if our students
actually knew why a radian is mathematically but not
operationally dimensionless and therefore why it's OK
to "drop" it in an expression like v = omega*r. If you
have first year students, I'd suggest asking them for
a physical interpretation of the slope of straight
line graph. I'll bet not one in ten says anything even
close to: For every one unit rise in the independent
variable, the dependent variable increases (or
decreases) by X units. Clear operational definitions
of physical quantities are key for development of
solid conceptual understanding in our students.

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