[Phys-L] two months old: Re: inertia and the tablecloth demo

[bernard cleyet <bernard@cleyet.org>]

"In short: When a body is pushed or pulled, the force and the acceleration occur simultaneously, and if they didn’t, Newton’s Second Law would be a heck of a lot more complicated than this:  …"

from the link below

Likely my knowledge is deficient, but assuming it’s not, I disagree.  Until GR, yes, but now, simultaneity is not ensured.  Tho the delay may be femto s.

bc not certain he understands.

> On Aug 19, 2016, at 3:42 PM, Anthony Lapinski <alapinski@pds.org> wrote:
>
> As I stated before, my students (regular and honors) find forces to be the
> hardest topic. The third law is particularly challenging. A book rests on a
> table. If the book's weight (true weight, mg) is the action force, then the
> reaction force is the ___ on the ____ acting _____. Nobody gets this right!
>
> On Fri, Aug 19, 2016 at 6:24 PM, Derek McKenzie <derek@physicsfootnotes.com>
> wrote:
>
> > Richard Tarara said:
> >
> > Actually I have always been baffled by the fact that many students DO
> > NOT seem to know what you mean by push/pull or even up/down. In
> > exercises to identify the 3rd law force pairs various situations, one
> > (too) often gets a mish-mash of pushes for pulls, pulls for pushes, and
> > often in the wrong directions. :-(
> > -----------------------------------
> >
> > That surprises me actually. In any case, just to be clear, I am not a
> > fan of identifying a force with a push/pull. As I argue in the following
> > post:
> >
> > http://physicsfootnotes.com/force-does-not-cause-acceleration/
> >
> > it's best to keep cause/effect language out of it. Necessary even!
> >
> > Derek McKenzie