Re: Apparent weight

[Leigh Palmer <palmer@sfu.ca>]

> Hi Leigh:
>
> Writing a long book is a time-consuming activity. What about about a
> sequnce of messages for those of us who certainly have something to learn
> from you in this thread?

I'm here to learn from everyone else. I'm now very tired of this thread.
What I've learned is that many people (many of whom are physics teachers
like me) are unwilling to accept the simplest conceptual presentation of
weight, even though it is completely valid and utterly conformal to
intuition. A simpler concept I couldn't imagine; naive students are less
likely to suffer misconceptions about weight than any other physical
quantity I could name. It appears that the only students who will have
problems are those who have been exposed to some strange indoctrination
that seems to occur in some physics classes! Incidentally, the only
"misconception" that is likely to arise is the confusion of weight with
mass. This is understandable; we should all be initially surprised that
there is a force acting on every mass within a frame of reference which
is proportional to that mass, and which has no proximate material cause
- it just seems to be there. The misconception can be cured by putting
the student in a different frame of reference and showing her that her
weight depends on the frame as well as her mass. The confusion would not
exist if weight were independent of inertial mass.

> Little hints here and there are not sufficient.
> I applaude you when you say that centrifugal forces are real. How can
> be any doubt about this? But people avoid them because they present the
> problem --> "what is the cause"? How do you deal with this?

I don't need a cause. The cause is usually described as a local property
of spacetime called "curvature", but that doesn't illuminate anything
for me (I don't understand general relativity). Perhaps David Bowman can
help us out a bit. My particular orientation is to accept what I can
describe without requiring a particular cause. It is utterly manifest
that centrifugal force exists; how anyone can be oriented otherwise I
can't understand.

> Also elaborate on the "tidal" nature of your "microgravity".

I think that was a misunderstanding. It has been cleared up.
"Microgravity" is a field which deals with phenomena in a weightless
environment.

> This will not make you rich, but, as we are often reminded, bread alone
> is not enough to make us happy.

No, indeed! I prefer cake, and money and sex are good, too.

Your encouragement also helps, Ludwik. I'm not being a very successful
teacher here, I'm afraid.

Leigh