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Ball on turntable

Started bySerigo <invalid@invalid.com>
First post2016-09-28 10:44 -0500
Last post2016-10-04 11:18 -0500
Articles 7 — 5 participants

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  Ball on turntable Serigo <invalid@invalid.com> - 2016-09-28 10:44 -0500
    Ball on turntable HVAC <mr.hvac@gmail.com> - 2016-09-28 11:53 -0700
      Re: Ball on turntable Serigo <invalid@invalid.com> - 2016-09-28 15:48 -0500
    Re: Ball on turntable "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-09-29 13:11 -0700
      Re: Ball on turntable "hanson" <hanson@quick.net> - 2016-09-29 13:49 -0700
        Re: Ball on turntable rbrteline@gmail.com - 2016-10-03 13:13 -0700
          Re: Ball on turntable Serigo <invalid@invalid.com> - 2016-10-04 11:18 -0500

#598656 — Ball on turntable

FromSerigo <invalid@invalid.com>
Date2016-09-28 10:44 -0500
SubjectBall on turntable
Message-ID<nsgohb$1t56$1@gioia.aioe.org>
college level physics problem


A ball with uniform mass density rolls without slipping on a turntable.

Show that the ball moves in a circle (as viewed from the inertial lab 
frame), with a frequency equal to 2/7 times the frequency of the turntable.



[hint: assume angular velocity of turntable, then of the ball, and 
realize the friction force from  the turntable is responcable for 
changing both the balls linear momentum and its angular momentum.  I 
classify this problem as hard. ]

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#598684

FromHVAC <mr.hvac@gmail.com>
Date2016-09-28 11:53 -0700
Message-ID<d8b5ce1b-8ba5-4051-a3e6-b9f239de57b8@googlegroups.com>
In reply to#598656
Not only hard but thought provoking. So many forces to consider. I assume I can ignore Coriolis factors?

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#598704

FromSerigo <invalid@invalid.com>
Date2016-09-28 15:48 -0500
Message-ID<nshaai$sgi$1@gioia.aioe.org>
In reply to#598684
On 9/28/2016 1:53 PM, HVAC wrote:
> Not only hard but thought provoking. So many forces to consider. I
> assume I can ignore Coriolis factors?
>

yep, I declare this problem is too hard, it has moment of inertia of the 
ball in it, and 8 equations

see solution 21
https://www.physics.harvard.edu/academics/undergrad/problems

also checkout problem 3, where they prove a pencil can only be balanced 
on its tip for a max of 4 seconds, by anything.

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#598854

From"reber g=emc^2" <herbertglazier0@gmail.com>
Date2016-09-29 13:11 -0700
Message-ID<9dc028b1-ad98-43e0-9236-0d5d959aafaf@googlegroups.com>
In reply to#598656
On Wednesday, September 28, 2016 at 8:44:47 AM UTC-7, Serigo wrote:
> college level physics problem
> 
> 
> A ball with uniform mass density rolls without slipping on a turntable.
> 
> Show that the ball moves in a circle (as viewed from the inertial lab 
> frame), with a frequency equal to 2/7 times the frequency of the turntable.
> 
> 
> 
> [hint: assume angular velocity of turntable, then of the ball, and 
> realize the friction force from  the turntable is responcable for 
> changing both the balls linear momentum and its angular momentum.  I 
> classify this problem as hard. ]

Ball not being a perfect sphere adds to its friction.All this shows its gravity all the way. Trebert

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#598861

From"hanson" <hanson@quick.net>
Date2016-09-29 13:49 -0700
Message-ID<nsjutu$1s3$1@dont-email.me>
In reply to#598854
"reber g=emc^2" <herbertglazier0@gmail.com> wrote:
"All this shows all the way that Trebert Glazier's "g=emc^2" 
is short for "Glazier Exhibits Micro Cephalic Cretinism

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#599294

Fromrbrteline@gmail.com
Date2016-10-03 13:13 -0700
Message-ID<77e6e4f3-508c-4401-8371-0485cd5b8700@googlegroups.com>
In reply to#598861
he probably had an i.q, at one time, but
it aint much more than pi, now.

the turntable is on the ball!

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#599406

FromSerigo <invalid@invalid.com>
Date2016-10-04 11:18 -0500
Message-ID<nt0kp7$1eis$1@gioia.aioe.org>
In reply to#599294
On 10/3/2016 3:13 PM, rbrteline@gmail.com wrote:
> he probably had an i.q, at one time, but
> it aint much more than pi, now.
>
> the turntable is on the ball!
>

relitivity states the turntable is on the ball, and the ball is on the 
turntable, at the same time. Now if the observer is on the ball....

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