Re: force

[John Mallinckrodt <ajmallinckro@CSUPomona.Edu>]

On Tue, 29 Oct 1996, Joseph Bellina wrote:

> It seems to me that acceleration is an observable, but you have to be 
> taught how to observe it, whereas force is unfortunately, a bit of a 
> figment of our imagination.  I go for the observable first.

Joe,

Can you be more explicit about your contention that acceleration is
somehow "more observable" than force?  Qualitatively we may be able to
"directly perceive" an object changing its state of motion, but it seems
to me that "observing"  acceleration in any quantitative fashion requires
a large number of pretty complicated calculational steps that take you a
long way beyond the required measurements of position and time.  Frankly,
I don't see that the force exerted on your hand by a compressed spring is
any less directly perceptible than acceleration and I might even argue
that it is more so.  It certainly offers a more visceral impression.  And
it's far simpler to attach a quantitative value to that force through the
measurement of how far the spring compresses and a simple procedure that
establishes its relative stiffness.

John
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