Re: The old loop-de-loop

[Bob Sciamanda <trebor@VELOCITY.NET>]

The Millikan terminology comes from the tendency of early texts to observe
that traditionally there are two different uses of the term "centrifugal
force":
1) A fictitious force acting on all objects viewed from a rotating reference
frame.
2) In inertial frames, the real outward force which acts on the agent which
is providing the (real) inward centripetal force on an object.

Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
http://www.velocity.net/~trebor/
trebor@velocity.net which is providing the
----- Original Message -----
From: "John S. Denker" <jsd@AV8N.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Sunday, November 16, 2003 9:38 AM
Subject: Re: The old loop-de-loop


> On 11/16/2003 09:52 AM, Ludwik Kowalski wrote:
>  > Why does a constraint force appear
>  > (in the laboratory frame) when an object slides inside a
>  > vertical loop? Note that I did not ask how to calculate
>  > the constraint force; the question was qualitative.
>  >
>  > We know how this question used to be answered in old
>  > physics textbooks. Millikan, for example, would say that
>  > the constraining force is the normal reaction force to the
>  > centrifugal force. But I am not allowed to say this because
>  > centrifugal forces "do not exist" in inertial frames of
>  > reference.
>
> 1) We regret that Millikan blurred the distinction between
> a rotating object and a rotating frame of reference.  That's
> a common mistake.
> . . .
.