Key Leads and Inertia

[David C. Stanwood]

>Any method that measures U and D weights is still measuring static 
>friction. Adding the extra weight to the hammer just increases the 
>static weight that is common to the DW and UW formulas. Not sure what 
>the reasoning to keep the jack under the knuckle is.

>Stephen

Stephen,

During acceleration the parts are thrown against each other as they resist
being moved so the normal force between rubbing surfaces is increased along
with friction.  Adding say a 50 gram weight to the hammer creates a similar
situation so that one could at least get a feeling for the increase of
friction during playing..  I can't imagine a jack will return under the
knuckle with a 50 gram weight on the hammer so I suggest tying down the
jack to maintain similar friction with U & D Wt.  

David S.