Re: [Phys-l] circular motion FBD

["LaMontagne, Bob" <RLAMONT@providence.edu>]

As a figure skating judge, I see lots of people walk out on rink ice and fall. The majority fall just the way cartoonists depict - their feet fly forward and they end up on their butts.

Bob at PC

> -----Original Message-----
> From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
> bounces@carnot.physics.buffalo.edu] On Behalf Of Bob Sciamanda
> Sent: Tuesday, November 01, 2011 12:33 PM
> To: phys-l@carnot.physics.buffalo.edu
> Subject: Re: [Phys-l] circular motion FBD
>
> Indeed, even without an already acquired forward momentum, the
> backward thrust of a foot must come from an internal force pair which will
> thrust the rest of the body forward.
>
> -----Original Message-----
> From: Bob Sciamanda
> Sent: Tuesday, November 01, 2011 12:03 PM
> To: phys-l@carnot.physics.buffalo.edu
> Subject: Re: [Phys-l] circular motion FBD
>
> I think one must consider the common case in which the walking individual
> already has a forward momentum.  When he then steps on a "frictionless"
> banana peel his forward foot will indeed slip backwards, but his C.M will
> continue forward - with a resulting rotation.
>
> -----Original Message-----
> From: John Mallinckrodt
> Sent: Tuesday, November 01, 2011 11:46 AM
> To: Forum for Physics Educators
> Subject: Re: [Phys-l] circular motion FBD
>
> Anthony Lapinski wrote:
>
> > I think the banana peel reduces the friction coefficient, and thus the
> > static friction force is reduced. Your push backward exceeds this, so
> > you slip backward.
>
> As Robert Cohen wrote, this isn't what most folks, especially cartoonists,
> think happen and I'm inclined to agree with them
>
>   http://bit.ly/vQ5mAP
>
> John Mallinckrodt
> Cal Poly Pomona
>
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> Bob Sciamanda
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> Bob Sciamanda
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