[CW] Regarding the slowing down of bugs......

[D.J.J. Ring, Jr. via CW]

Steve,

You're talking about a gravity (or simple) pendulum, not a physical (or
compound) pendulum.  With a physical (compound) pendulum the period and
frequency depend on the length of gyration, the moment of inertia and the
MASS of the PENDULUM.

It's also measured to the center of gravity when calculating the pendulum
length, thus lots of weight concentrated on the end of the vibrator makes
the key send slower than if the same weights were distributed closer to the
origin of the vibrator - and this is what we see when we move the weights
towards the operator on a normal Vibroplex key.

*What is the difference between Simple and Compound Pendulums?*

• The period and, therefore, the frequency of the simple pendulum depends
only on the length of the string and the gravitational acceleration. The
period and the frequency of the compound pendulum depend on the length of
gyration, the moment of inertia, and the mass of the pendulum, as well as
the gravitational acceleration.

• The physical pendulum is the real life scenario of the simple pendulum.

73

DR

On Sun, Dec 21, 2014 at 12:07 PM, Steve WD8DAS via CW <cw at mailman.qth.net>
wrote:

>
> I've never understood the idea of slowing down a bug by adding weight.
> The swinging dit arm is a pendulum, and the period of a pendulum is
> controlled by the length of the arm, not the weight.  You move the weight
> farther back to make the pendulum arm longer and slow it down.  When you've
> reached the end you have to add an extension to the arm (which I did as a
> kid using the shank of a blank house key) to go even slower.
>
> On a pendulum wityh a small amplitude of swing like on a bug, adding
> weight without lengthening the arm will make it close the dit contact for a
> longer time, changing the length of the dits,but the speed would not be
> changed.
>
>
>  Steve WD8DAS
>
> sbjohnston at aol.com
> http://www.wd8das.net/
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