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nberme52
12-12-2000, 12:20 AM
Here is more on centrifugal force!!

In mechanics, when all forces and moments acting on a body are shown (i.e.
the "free body diagram"), it is customary to use "inertia forces" to ensure
equilibrium. An inertia force is a force equal and opposite to the net
acceleration multiplied by the mass of the body. That is, it is equal and
opposite to the external force acting on the body. For an object to move on
a curved path, an acceleration directed towards the center of rotation is
necessary (otherwise the object will maintain a straight-line path). This
acceleration is one of the "normal" components of acceleration (the other
normal component is the "coriolis" acceleration). The "centrifugal force" is
the inertia force corresponding to this normal component of acceleration. It
may be an imaginary force, if you like, - but an absolutely necessary one if
the equilibrium equations are to be valid.

Necip Berme, Ph.D.
Professor, Mechanical Engineering
The Ohio State University
206 W 18th Avenue
Columbus OH 43210

Phone: 614 292-0859
Fax: 614 430-5425
E-mail: berme.1@osu.edu

----- Original Message -----
From: Gary Christopher
To:
Sent: Monday, December 11, 2000 9:31 AM
Subject: Centrifugal Force

In teaching and studying Biomechanics I have used three textbooks, all of
which mention, and then try to justify, the existence of centrifugal force.
Yet if I check my physics book it tells me flat out that there is no such
thing. What is the biomechanics community's take on the subject?

Just so you know my personal leanings, I don't put any stock in its
existence, so I'm left trying to convince my students why I'm right and
their textbook is wrong.

If we all believe Newton's Second Law of Motion, we should be able to easily
determine that the so-called "centrifugal force" is, in fact, fantasy. If we
believe Newton's Second Law, we should scoff at the notion of a force that
does not have an accompanying acceleration.

As is customary, I will post a summary of responses. Please reply directly
to my email: gac6@email.byu.edu

Gary Christopher
Brigham Young University

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