The spring constant dictates the period
and all simple extension springs seem to behave according
to the period and length of a pendulum.
If you need 10 to 12 inched of wire to make a
1 second pendulum then whatever weight of mass
will cause the sprint to drop ten or twelve inches
from rest will give you the same period.
This assumes no pretensioning of the extension spring
and that it is linear in its response.

The inches/pound spring constant will dictate the period
depending upon the weight/mass applied.

The longer the spring the more intense the temperature affects
I do not know how to deal cheaply with the physical constants
that are a nusance.

Regards;
geoff

----- Original Message ----- 
From: "Jerry Payton" 
To: 
Sent: Wednesday, July 18, 2007 13:49
Subject: Mass vs. Coil


> You gentlemen are so much advanced and more educate than I that I almost 
> hesitate to ask this question.  A lot of your discussions, especially math 
> and physics, go right over my head.  However, here goes:
> 
> I have always wondered why a mass is needed.  Why could not the coil itself 
> be used as the mass on a pendulum seismometer?
> 
> If  I understand what I have read in my books (questionable), the size and 
> weight of a mass has nothing to do with the period.  Futhermore, I believe 
> the length of the pendulum and supporting spring or wire on a horizontal or 
> vertical sensor matters more for obtaining the wanted period, excluding 
> friction loses etc.  The coil is only the desired method of detecting 
> movement.
> 
> Regards,
> Jerry Payton
> 
>
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