Re: little gee and its sign

[Bernard Cleyet <anngeorg@PACBELL.NET>]

Like so many experiments what may be ignored depends on the technology.  With
the increasingly used advanced technology in intro. labs, I expect that soon
"... air resistance with free fall ..." will not be ignorable.  Already
advanced labs have nanosec. and sub micron resolution.  Squires for example
describes a rather sophisticated and elegant method of measuring g using a
servo controlled falling chamber in a vacuum enclosure.  It claims ~ one micro
Gal error.  Admittedly this is a research instrument, but a simplified version
without the vacuum and falling chamber part would show the air friction and not
be beyond the typical advanced lab or an intro. lecture demonstration.

bc


Rick Tarara wrote:

> ----- Original Message -----
> From: "Larry Smith" <Larry.Smith@SNOW.EDU>
> To: <PHYS-L@lists.nau.edu>
> Sent: Wednesday, September 12, 2001 11:01 AM
> Subject: Fwd: Re: little gee and its sign
>
> > At 11:12 PM -0600 9/10/01, Jim Green wrote:
>
> > > I also don't understand why an instructor would introduce the concept of
> > > acceleration with free fall -- pedagogically this is nuts.
>
> Free fall IS the most available example of objects accelerating at a
> constant rate and is therefore prime fodder for kinematics problems.  Almost
> all of the other accelerations that are made up for kinematics problems are
> unrealistic.  OK--we have to ignore air resistance with free fall, but when
> I drop a bowling ball from 2-3 meters above the floor, air resistance _will_
> be ignorable.

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