Re: [Phys-l] Centrifugal redux

[Bernard Cleyet <bernardcleyet@redshift.com>]

John!  I do believe you're being difficult!

It's either a joke or in this age of expensive fuel a suggestion that  
such an exercise is not appropriate, even hypothetically w/ out the  
caveat.

bc prays he's not missing something, i.e. another one of his many Sr.  
Moments.

p.s. Sr. Moment exposed:  small planes circle airfields 'till it's  
their turn.

On 2009, Mar 17, , at 14:48, John Denker wrote:

> On 03/17/2009 11:56 AM, LaMontagne, Bob wrote:
> > When I was getting my sailplane license I remember having to learn in
> > ground school that the inward component of lift when going in a  
> > circle
> > is just balanced by the centrifugal force.
>
> So far so good.
>
> > My question as to why you
> > would then fly in a circle was not welcomed by the instructor.
>
> Answer:  You're flying in a circle by hypothesis.  That is,
> it's a premise of the scenario.  If you weren't flying in
> a circle there wouldn't be any centrifugal field.
>
> The principle is simple:  The centrifugal field exists if and
> only if you are using a rotating reference frame.
>
> This is covered in the text starting at
>   http://www.av8n.com/how/htm/motion.html#sec-rotation-intro
>
> John S. Denker
> Advanced and Instrument Ground Instructor
>
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