PSN-L Email List Message

Subject: Re: pendulum similar to the one mentioned
From: tchannel1@............
Date: Thu, 27 Mar 2008 12:35:52 -0600

Hi Randall,  So If I understand this,
1. below the pivot would be 50cm
2. above the pivot would be 2.5cm
3. the top mass would be 10x the lower mass.
4. an adj mass as shown to balance, at rest, vertically
5. a resulting period of about 20 seconds

Q.  At this point it is undampered, Would I add a damper, or try it with no 

Thanks, Ted

----- Original Message ----- 
From: "Randall Peters" 
Sent: Thursday, March 27, 2008 12:06 PM
Subject: pendulum similar to the one mentioned

> Ted,
>     I built a pendulum that is similar to the one that has been
> simulated, except that it was configured to optimize sensitivity at a
> period of about 4 s (to study microseisms).  It is described at the
> following site by the paper titled "Compound pendulum to monitor
> hurricanes and tropical storms"::
> To convert the instrument shown in Fig. 1, the lower (lead) mass would
> be discarded, and the upper (lead) mass would be lowered nearly all the
> way possible (just above the axis, after which the upper tube would be
> sawed off just above the mass).


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