pendulum

[Randall Caton]

I apologize if someone already posted a pendulum solution. Attached is a
Squeak solution to the problem assuming the small angle approximation
(theta is approximately sine theta) and starting the pendulum from rest.
It uses the same motion ideas of position, velocity, and acceleration as
the freefall problem already discussed. It uses simple Squeak blocks to
approximate the solution by solving two first order differential
equations numerically and displaying the result as a moving pendulum -
very similar to the freefall problem. The added twist is that the
acceleration depends on position (in this case an angle). It could be
the next problem after freefall. I'm not sure how to teach it to young
kids, but if they got the freefall problem, then ask them: "Now what if
the acceleration isn't constant? Let's find out."

You can experiment to see the effect of mass, gravity, and length. There
is no effect from mass - it is put in because it is a common
misconception. Probably there should be an angle watcher so that
starting angle could be varied, however the simple solution modeled here
breaks down for large angles and that would have to be carefully
explained.

Randy Caton

--
I am on leave from Christopher Newport
University from Fall 2002 to Fall 2004.
I will be at NASA Langley Research Center.
However, I will still use rcaton at cnu.edu
as my email.

Randall Caton
NASA Langley Research Center
Hampton, VA 23681-2199
voice: 757-864-5032
FAX: 864-8835
email: rcaton at cnu.edu
web: www.pcs.cnu.edu/~rcaton

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