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Re: [Phys-l] irresistible force v. immovable object



I feel like I'm on Punked right now, just waiting for Ashton Kutcher to
reply to this email and tell me I'm not crazy. Ashton? Are you there?

The only way you end up with an infinitesimal acceleration, in the strictest
sense, is if you permit infinity (in big or small form) with regard to force
and mass. If you claim a big, yet finite mass, then any net force will
accelerate the mass by a finite amount. If we're in any way thinking of
involving calculus, then we have to be okay with calculus-based results.

I respect your suspicion that space/time is quantized, but let's keep in
mind that we're dealing with introductory physics students here, and the
discussion is in that context.

On Wed, Feb 23, 2011 at 4:15 PM, chuck britton <cvbritton@mac.com> wrote:

At 2:35 PM -0500 2/23/11, Mike Viotti wrote:
Just to further pound home my point, this is a perfect teaching example
about the impossibility of an immovable object. F = ma says that any mass
can be accelerated with even the most minuscule of net forces. THAT is
the
teaching moment, in my opinion.

But it's an infinitesimal acceleration - so I don't see that this is
any sort of 'final' argument.

Infinitesimals are not allowed in some 'maths'.
I suspect that space/time is quantized.
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