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Re: speed and velocity



On Wed, 25 Nov 1998, Dewey Dykstra, Jr. wrote:

The problem with the "<" and ">" symbols is that they are mis-named. The
names given them are about magnitudes ("less than" and "greater than") but
the actual function they serve is to indicate direction on a number line.
The names we give them are only appropriate when both numbers are on the
positive side of zero. If you look you will notice that the symbols taken
as arrow heads (vector heads) they always point toward the number nearer
negative infinity on the number line. The names (in English anyway) do a
real disservice.

Dewey,

I think this is a little overly general. I agree with the concern
expressed about saying that -4 m/s is "less than" 2 m/s. But there are
plenty of times when the standard convention is exactly what we mean. An
altitude of -200 m *is* less than an altitude of +100 m; -20 degrees C
*is* less than +10 degrees C; etc.

John
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A. John Mallinckrodt http://www.csupomona.edu/~ajm
Professor of Physics mailto:ajm@csupomona.edu
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