Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Causation in Physics: F=ma



On Thursday, Nov 13, 2003, John S. Denker wrote:

I think of static friction as a "responding" force. For
example, a crate pulled to the right (by a rope) will
experience a responding force (from the floor) directed
to the left.

That way of thinking anthropomorphises the force,
which is usually irrelevant and sometimes misleading.
F does not "cause" ma, and ma does not "cause" F,
for reasons discussed at
http://www.av8n.com/physics/causation.htm

In that reference JohnD discusses the "A causes B"
in general and F=m*a in particular. The section ends
with a conclusion "The F=ma equation cannot shed
any light on causality relationships."

Does anybody know an introductory physics
textbook (calculus or non-calculus based) in
which forces are not treated of "causes" of
things in mechanics? Those with which I am
familiar treat acceleration as being due to a
net force. Only in kinematics do they present
acceleration "without a cause."

John's message begs for another question.
What does it mean "to explain," in physics?
Ludwik Kowalski