Re: Newton's 3rd law? was Re: inertial forces (definition)

[Cliff Parker <cparker@EMPOWERING.COM>]

Leigh Palmer wrote:

>  The
> photon is a quantum mechanical entity. It is certainly no less
> unreal than the electromagnetic field.

Good point.

> I do mind if you want to call weight
> the gravitational force. There's no justification for that when
> you look around *inside* the laboratory, and besides, with outside
> knowledge we know that isn't even right; the weight includes a
> centrifugal component that registers on a scale even if you don't
> believe in it. From experiments done inside the laboratory you
> can't tell if you are accelerating in a rocket ship, or at rest on
> Earth's surface, or as John Mallinckrodt points out, hovering in
> a rocket ship one meter above a launchpad on Earth. Inside the
> laboratory all situations lead to the same physical results for
> experiments.

Do you actively work to dispel the idea that weight is caused by gravitational
force in your intro class?  Do your students understand the subtleties of your
language choices or are you just being careful so as not to be responsible for
misconceptions at a later date?   Do you connect the downward motion of falling
objects with the circular motion of orbits or is that not part of your study of
Newtonian physics in the Earthbound laboratory and saved for as you said later on?

Cliff Parker