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



Let me be clear. I'm not saying inertia is really a cause because we know in the Newtonian context we do not need one but in our instinctive aristotlean framework we think we do so we give it a name inertia. It then becomes part of the conversation even though it is meaningless and confusion results
Another example of giving something a name is heating is the process of doing something that raises the temperature to increase and so in answer to what has been added we nominalize the verb to create the word heat causing all sorts of difficulty.

Sent from my iPhone

On Aug 18, 2016, at 11:42 PM, Anthony Lapinski <alapinski@pds.org> wrote:

Regarding these two comments:

I get that there is no absolute rest in the universe.

And nobody knows why things continue to move with constant velocity in the
absence of a force. However, not sure if the "property" of inertia "causes"
this. This is similar to gravity -- nobody really knows why objects fall
(are attracted to each other) when released.

As my college physics teacher often said, Physics explains how, not why.

On Thu, Aug 18, 2016 at 11:28 PM, Joseph Bellina <inquirybellina@comcast.net
wrote:

Two comments
First the notion of at rest is a fiction since it depends on your inertial
frame of reference.
Second. It seems to me that in spite of our understanding there is still
an element of mystery associated with the way objects continue to move in
the absence of a force, so we need a cause so we give the object a property
we call inertia. In that sense ir is an empty concept in a Newtonian world
and has a deferent only in an aristotlean world

Best

Joe

Sent from my iPhone

On Aug 18, 2016, at 10:55 PM, Anthony Lapinski <alapinski@pds.org>
wrote:

I would not equate the first law with conservation of momentum. If an
object is at rest, it has no momentum but still has mass (intertia).

On Thu, Aug 18, 2016 at 10:40 PM, Richard Tarara <rtarara@saintmarys.edu

wrote:

Except that Newton's First Law is often referred to as the Law of