Re: [Phys-l] g...

["Bob LaMontagne" <rlamont@postoffice.providence.edu>]

> -----Original Message-----
> From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
> bounces@carnot.physics.buffalo.edu] On Behalf Of Hugh Haskell
> Sent: Monday, November 20, 2006 12:47 AM
> To: Forum for Physics Educators
> Subject: Re: [Phys-l] g...
>
> At 11:09  -0500 11/19/06, John Denker wrote:
> > I need the next level of detail here.  Taken separately, several
> > steps in that argument make sense.  Taken collectively, they don't
> > add up;  they don't suffice to support the conclusion.
> OK. I'm leaving out too many steps here. The reason I assert that g
> should not be considered an acceleration is because we can consider
> the general case of a field acting on an object through some
> mechanism, call is the "field-susceptible property." In the case of
> gravity, that is gravitational mass. In the case of electricity that
> is charge (for the moment, call that "electrical mass" merely to
> illustrate the analogy). In the general case the force on an object
> subject to that particular field is
>
> Force = (Field susceptible property) x (Field strength)

I'm a little confused with this approach. It implies a universality of sorts
- but how many types "forces" does it actually represent? Gravity and the
Coulomb force seem to fit - possibly the strong and weak interactions too,
but it's not clear to me that they fit smoothly into this equation.

Then consider the magnetic interaction. How do you fit the velocity
dependence on the "field susceptible property" (- i.e., the moving charge}
into this algorithm?

However, I am in agreement with avoiding the defining of g as an
acceleration - it makes no sense to the student when an object is lying on a
table. Defining it as gravitational force per unit mass (or as the field)
seems far less confusing.

Bob at PC