Re: [Phys-l] question on averaging.

[Brian Whatcott <betwys1@sbcglobal.net>]

Bernard Cleyet wrote:
> I'm analyzing the free decay of a pendulum à la Siegel [AJP 76 (10)  
> 956.]
>
> However, the pendulum has such a large Q (few hundred => ~2k) that I  
> must average over several data points.  Since the necessary values  
> are the speed squared there are two orders.  One to average the  
> squared speeds and tother to square the averaged.  The difference is  
> not large as over most of the decay the loss is rather small. [Which  
> is why I must average!]  Also the factor of interest is the  
> difference between the squared points (speeds).  So the question,  
> which is the correct  order, if there is one?
>
> bc  thinks this is more a meta-physics question
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>   
Since you asked...

What is the purpose of averaging observations?
A desire to minimize observational errors.
How does one observe the speed of a bob?
One does not. (In my view)
One observes positions, deduces separation and observes elapsed time.
The deduced speed is given by a deduced separation and an observed time 
delay.
One (if one is me :-) then fits sequential speeds to curve of some 
deduced type,
by rms means.

BrianW