Re: [Phys-l] Centrifugal redux

[John Denker <jsd@av8n.com>]

On 04/01/2009 09:50 AM, Anthony Lapinski wrote:
> ... I attach a
> wood block to a spring scale and hold it up. Then ask: What does the scale
> read while they fall together? Less confusion.

Yup.  That's good.

I take it one step further and make an accelerometer that can be
turned upside down.  It reads +1 when upright and -1 when inverted,
to emphasize that acceleration is absolute (not relative, certainly
not relative to the lab frame, not zero in the lab frame).

Also you can attach a string to the accelerometer and swing it
around, to drive home the correspondence between the gravitational
field and the centrifugal field.  Both show up as an acceleration,
in accordance with Einstein's equivalence principle.

For details and pictures, see
  http://www.av8n.com/physics/accelerometer.htm