On 01/01/2017 12:30, Frank King wrote:
Dear All,
I hope you all enjoyed the extra second
in bed this morning and that your alarm
clock didn't go off one second early.
Here is an easy question to start off
the New Year...
Every Sunday at 08:00 I check the first
stroke of the hour-bell of the University
Clock against a radio-controlled UTC clock.
If it is slow I add coins to the tray on
the pendulum. If it is fast I remove
coins. My formula for the required
adjustment includes a figure for:
Last Week's Gain [LWG]
Here are my recent observations:
25 December clock 0.5 seconds fast
1 January clock 2.0 seconds fast
Is the appropriate figure for LWG:
a) 0.5 seconds
b) 1.5 seconds
c) 2.5 seconds
Frank
Frank H. King
Keeper of the University Clock
Cambridge, U.K.
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Dear Frank,
Happy New Year! I am sorry to hear that it starts with a problem for
you albeit one of the horological kind, so that removes the pain.
I am somewhat puzzled, too.
You say:
/Every Sunday at 08:00 I check the first stroke of the hour-bell of
the University Clock against a radio-controlled UTC clock. If it is
slow I add coins to the tray on the pendulum. If it is fast I remove
coins. /
Does the 'it' at the beginning of your second par. refer to the
University clock?
If so, then if it is slow (i.e. rings after the UTC clock says it
should), then its pendulum is too long (C.G. too low), so needs
shortening. So coins need to be removed, not added. This assumes that
the place where you add/remove the coins is below the current C.G.
As to the main question, between 25/12 and 1/1, the clock appears to
have gained 1.5 s. But the UTC clock has added a second, so the
University clock has gained only 0.5 s so the LWG is 0.5 s. In any
case, if the clock has not been tampered with, it is unlikely that the
University clock will have changed its previous LWG of 0.5 s to 1.5 or
even 2.5 s in the space of a week. So I'll go for 0.5 s as the correct
answer.
David.
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