🚀 go-pugleaf

Subject:      Friction?
To:           Multiple recipients of list PHYSHARE <PHYSHARE@PSUVM.PSU.EDU>

>Friends If you have an activity that can clearly DEMONSTRATE to a student
>that friction, and not gravity, is responsible for a ball oscilating to a
>stop in vertically, circular or parabolic track. If you have an activity
>that can clearly DEMONSTRATE to a student that friction, and not gravity,
>is responsible for bob of a pendulum coming to a stop on its string.
> Do you think that this is not a problem with your students?
>                Paul Hickman        From:  Namkcihp@AOL.COM

Hello Paul:

For the pendulum I would suggest to increase the air resistance (friction)
by increasing its effective cross secion, for example, with a styrofoam
board (negligible change in gravity). This should demonstrate how the rate
at which amplitudes are decreasing is affected. A four string suspension
system would be desirable to prevent rotational motion. Doing this in front
of a motion detector, if available, would facilitate data analysis. I think
that five to ten fold increase in the effective cross section should be
sufficient. Please let us know how this works, if you try it.

                   Ludwik Kowalski      kowalski@apollo.montclair.edu