Re: F=ma

["Shapiro, Mark" <mshapiro@EXCHANGE.FULLERTON.EDU>]

Joel,

        Is this really correct?  I know that some "force" measuring devices
measure accelerations, but don't strain gauge type devices also measure
"forces".

        Nevertheless, I do agree with those who view F=ma or (more
correctly) F=d(mv)/dt as a prescription for measuring or calculating forces.

Mark Shapiro
http://www.IrascibleProfessor.com

-----Original Message-----
From: Joel Rauber [mailto:Joel_Rauber@SDSTATE.EDU]
Sent: Sunday, November 07, 1999 10:08 AM
To: PHYS-L@lists.nau.edu
Subject: Re: F=ma


> There two
> problems:  (1) It is almost impossible (if not actually) to
> measure *all*
> the forces without assuming the answer to the question of
> whether or not
> the sum of the forces is, first.  (2) We don't actually
> measure force.  We
> measure observable effects, experiences for which force is
> the explanation.
> Apparently "Nature" can't or won't tell us "the answer," so we have to
> decide based on other criteria.  Perhaps if we thought of
> force not as a
> causal agent, but an explanatory entity...

I can't resist pointing out that Dewey's post supports a position and
provocative statement I have made in the past.  Perhaps, the support is not
unequivocal, however.

"Force meters (gauges, what-have-you) work by measuring accelerations".

Dewey, where were you when I needed defenders?  :-))

Joel

Baaaa, I'm spending Sunday morning working on an introductory test, so I
needed a little diversion here.