Re: [Phys-L] field of an ellipsoidal distribution

["Bob Sciamanda" <treborsci@verizon.net>]

Given a perfectly spherical rigid earth, and a table whose horizontal 
surface is perpendicular to the earth radius, the centrifugal force on an 
object resting on this horizontal surface has a horizontal component (very 
small in the real situation).

-----Original Message----- 
From: Carl Mungan
Sent: Friday, August 14, 2015 2:37 PM
To: PHYS-L
Subject: Re: [Phys-L] field of an ellipsoidal distribution

Hmm… define what you mean by a “horizontal” tabletop. Are you telling me 
that I should not expect a puck placed on a horizontal air hockey table to 
remain at rest?

> On Aug 14, 2015, at 2:22 PM, Bob Sciamanda <treborsci@verizon.net> wrote:
>
> Carl wrote:
> "The YouTube video neglects a small correction by assuming that N points 
> in the
> radial direction. This is the old question of “which way does a plumb bob
> point” on a rotating earth point?  .  .  .
>
> Interesting ...  My spin is that the You Tube guy is not thinking of a 
> plumb bob - he is modeling an object resting on a horizontal table top at 
> the earth's surface.  Then his calculated N is indeed the normal force of 
> the table top on his test object.  In addition there is required a 
> frictional force from the table top to balance the horizontal component of 
> the centrifugal force.
> For a hanging bob model, the string must supply both components, as a 
> single tension force (T, not N).
>
> Bob Sciamanda
> Physics, Edinboro Univ of PA (Em)
> treborsci@verizon.net
> www.sciamanda.com
> _______________________________________________
> Forum for Physics Educators
> Phys-l@www.phys-l.org
> http://www.phys-l.org/mailman/listinfo/phys-l


-----
Carl E Mungan, Assoc Prof of Physics  410-293-6680 (O) -3729 (F)
Naval Academy Stop 9c, 572C Holloway Rd, Annapolis MD 21402-1363
mailto:mungan@usna.edu     http://usna.edu/Users/physics/mungan/

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Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
treborsci@verizon.net
www.sciamanda.com