Re: Linearizing Graphs

["Spagna Jr., George" <gspagna@RMC.EDU>]

Ed Schweber writes:


>   If we want to force a graph exeperimental data for period, T, of a
> pendulum vs its length, L, into being a straight line we usually plot T^2
> vs. L. But a graph of T vs sqrt(L) would also be linear and seems to be
> easier for students to understand. Is there any reason besides convention
> for doing it one way as opposed to the other?

>   When we linearize data for a discharging capacitor (potential, V, vs.
> time, T) I can see an advantage to plottimg lnV vs. T rather than V vs
> e^(-t). Is what we do with pendulums just a carry over of this pattern?


Maybe I'm getting old - why not plot T vs L on log-log graph paper?  You
should get a straight line (which tells you it's a power law).  The slope of
that line (1/2) will tell you the exponent.  A similar approach works for
capacitor data, too, but there you use semi-log graph paper.

**********************************************************
"Vocatus atque non vocatus - Deus aderit."
                               - Karl Jung
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George Spagna
Department of Physics
Randolph-Macon College
P.O. BOx 5005
Ashland, VA 23005-5505
phone: (804) 752-7344     FAX (804) 752-4724
e-mail: gspagna@rmc.edu
http://www.rmc.edu/~gspagna/