Re: causation

[Rick Tarara <rtarara@SAINTMARYS.EDU>]

I think the view expressed by many here has not been to look at F = ma as a
cause and effect equation, but rather to contend that accelerations
themselves are caused by forces (but forces are not caused by
accelerations).  The thinking goes--you want an object to accelerate.  How
do you accomplish such?  You apply a net force in the direction of the
desired acceleration.  Therefore, the acceleration can be said to be caused
by the applied force(s).   At least in the Newtonian scheme, all
accelerations require a net force and one or more agents that provide the
force(s).  I push the table, it accelerates.  Seems like a cause and effect
relationship?  In what scenarios (likely to be encountered in intro physics
instruction) is this not the case?

Rick

*********************************************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, Indiana
rtarara@saintmarys.edu
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----- Original Message -----
From: "John S. Denker" <jsd@AV8N.COM>
> Sometimes there are scenarios where something
> involving a force truly causes something involving
> an acceleration (and not vice versa).  But you need
> to deduce this based on details of the scenario other
> than F=ma, because there is nothing in the F=ma
> equation that specifies a direction of causation.
>
> On the other side of the same coin, sometimes there
> are scenarios where something involving an acceleration
> truly causes something involving a force (and not
> vice versa). But you need to deduce this based on
> details of the scenario other than F=ma.