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Re: definition of weight



Your summary of "weight" reminds me of the teacher who would tell anyone
who asked for the time how to build a watch and other time measurement
devices.
He would also present a long lecture on the meaning of time in different
contexts
and relativity time dilation effects . It certainly would be an
interesting discussion
in a Philosophy of Science course but I would hesitate to present it in
a typical
course of Introductory Physics.

Define "typical". I am specifically talking about the first part of
our 3-semester walk through Tipler. The title of the course is
"Physical Mechanics I" and it is for sophomore physics majors, about
12 students per section.

If you mean I enjoy going on at length about subtleties with physics
majors, then I'm guilty as charged. Of course, I don't do this every
class nor do I ever spend the whole hour on it. But yes, I love to
spend time on optional sections, toy in class with puzzles (such as
I've heard on PHYS-L), and generally follow rabbit trails and mess
around.

I guess the only thing I'd add is that what I've outlined in this
document is not to be presented in a single lecture. It's to be
gradually meted out as one walks through 1D Kinematics, then 2D
Kinematics, then Newton's Laws, then Gravity, then ... for the
"typical" course.

Around the middle of your second page there is a minor error " 2.2
kilograms
weighs one pound at the earth's surface". This would only be true only
at
some distance above (or below) the earth's surface.

Oops, I meant 1 kg weighs 2.2 pounds! (You knew that, right?)
Thanks for your comments, Carl
--
Carl E. Mungan, Asst. Prof. of Physics 410-293-6680 (O) -3729 (F)
U.S. Naval Academy, Stop 9C, Annapolis, MD 21402-5026
mungan@usna.edu http://physics.usna.edu/physics/faculty/mungan/