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Re: Causation in Physics: F=ma



The key phrase in the quote provided by Larry is
"the effects of forces on the motion of objects."
"Effects" implies that forces cause changes in motion.

The phrase was not "the relationship between forces
and changes in the motion of objects."

Daniel Crowe
Oklahoma School of Science and Mathematics
Ardmore Regional Center
dcrowe@sotc.org


-----Original Message-----
From: Larry Woolf [mailto:larry.woolf@GAT.COM]
Sent: Friday, November 14, 2003 2:10 PM
To: PHYS-L@lists.nau.edu
Subject: Re: Causation in Physics: F=ma


For those interested in how the National Science Education Standards handles
this:

<http://www.nap.edu/readingroom/books/nses/html/6e.html#ps>

"Objects change their motion only when a net force is applied. Laws of
motion are used to calculate precisely the effects of forces on the motion
of objects. The magnitude of the change in motion can be calculated using
the relationship F = ma, which is independent of the nature of the force.
Whenever one object exerts force on another, a force equal in magnitude and
opposite in direction is exerted on the first object."

Larry Woolf
General Atomics
3550 General Atomics Court
Mail Stop 78-110
San Diego CA 92121
Ph:858-526-8575
FAX:858-526-8568
http://www.ga.com
http://www.sci-ed-ga.org