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Re: [Phys-l] g...



The Wikipedia article is one such article.
http://en.wikipedia.org/wiki/Acceleration_due_to_gravity

The give both the measured g (called the gravitational acceleration) and the
calculated g from NTN gravitational law with 5 digit numbers. They then
mention that they do not agree because of various "corrections". The
distinction that the two numbers are actually different quantities is
implied, but not explicitly said. Then also claim that the answer (given to
4 sig digits) varies because of significant errors in the numbers used. Yet
the numbers used are 5 digits or more, so how can this contribute to the
variation?

The term gravity is used very loosely. While the article seems to be
accurate, the ambiguities in the use of terminology are quite apparent.

Then one would like from a pedagogical point of view see them use units on
all of the numbers. No wonder students are confused when they look at
reputable sources on the web. Professionals in the field simply pass over
these things because they understand what is being said, but students are
easily confounded.

John M. Clement
Houston, TX


Many of the sites I have seen do not make a clear distinction between the
acceleration of a body at the surface, and the gravitational field
strength.