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/snip/ The Cambridge Clock (Trinity College) has been examined in detail in order to ascertain if it can detect the g variation due to the moon. (1)
My interest is in its running Q. The escapement supplies energy (to the pendulum) from the drop of the gravity arm; mass 50 g thru 3mm every 1.5 seconds. (three second period)
The bob's mass is 104 kg (calculated from other data, i.e. not measured directly), and the running amplitude is 55mrad.
/snip/
The alternate is to separately find the pendulum’s energy and divide it by the escapement energy.
This is a method described by Woodward (2) in, IIRC, "My Own Right Time” to find the running Q.
/snip/
p.s. Assumptions and approximations include: zero rod mass and bob a point. And I did not obtain the published value from the keeper of the clock reported by Drumheller. (3) (bc=> 7358 Dr. Hunt, fellow Trinity College: 4570)
(1) Lupton, R. The Trinity Clock
http://trin-hosts.trin.cam.ac.uk/clock/?menu_option=theory
(2) Philip Woodward - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Philip_Woodward
(3) Drumheller, Douglas S.; Barometric compensation of pendulum JAM-11-1236 (copy supplied by the author. The shorter article in the HSN doesn’t include this information.)