Re: [Phys-l] interaction

[John Denker <jsd@av8n.com>]

On 08/02/2007 12:53 PM, Jeffrey Schnick wrote:
> Information indicating that if you talk more about interactions than
> about one object exerting a force on another then students will gain a
> better understanding of Newton's Third Law has convinced me that I
> should use the word "interaction" more often in my introductory physics
> course.  As such, I want to make sure that I have a clear understanding
> of how physicists use the word.

That's a good clear question, but there is not going to be 
a comparably clear answer.

"Interaction" is a word physicists use when we don't want
to be precise, so looking for a precise meaning is futile
and/or a step in the wrong direction.

For example, when we say "Coulomb interaction" you don't
know whether that refers to the electrostatic force and/or
the electrostatic energy and/or the static electric field.
You can't write an equation
  Interaction = .....
in contrast to the more-specific things mentioned above:
  Force = ....
  Energy = ....
  Field = ....

Interaction is a useful catch-all term.

In the context of the third law, if you mean "force pair"
it might be best to say "force pair".