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Re: Centripetal force and TPT article



I don't see what all the fuss is about.

It seems to me that the term "centripetal force" is a
shorthand for "the centripetal component of the force"
and unless context requires otherwise, that in turn is
shorthand for "the centripetal component of the total
force".

This terminology parallels other bits of terminology,
such as "normal force" and "lift" and "drag" and many
others; it says nothing about the physical origin of
the force.

This terminology stands in marked contrast with another
class of terminology, such as "gravitational force" and
"centrifugal force"; these latter terms do say something
about the physical origin of the force.

In general, any force can be decomposed into various
contributions. This decomposition is verrrry highly
non-unique:
-- You can decompose it into components.
-- You can decompose it according to physical origin
(gravitational, centrifugal, electromagnetic, ....)
-- You can decompose the contributions from various
bodies in an N-body system
-- etc. etc.
-- Combinations of the above.


When you see some authors put an adjective in front
of the word "force", you should not assume they are
claiming to have discovered a new law of nature; it's
probably just a new decomposition of the known laws.



Bernard Cleyet wrote:

Wait a min -- I thought centripetal force was the "real" force (what
keeps the bob from observing the 1st law, and c-fugal was the frame force
(pseudo or unreal force).


Earlier Bernard Cleyet wrote:

When ever you see the phrase "centrifugal force" consider it a red flag.

Huh? What brought that on?

Centrifugal forces are as real as gravitational forces.
They arise whenever we analyze things in a rotating frame.