Resilience and energy transfer, was Acetone

Michael Spalding spalding48@earthlink.net
Fri, 23 Apr 2004 06:56:58 -0500


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Isaac,

I'm relying on decades-old memories of college physics for this, so the details may not be exactly right, but I think I have the general principals correct.  Resilience is a measure of how little energy is absorbed, and lost to conversion to heat, by a material when compressed:  the more resilient the hammer, the less energy it absorbs during collision with the string.  As to the other question, how much energy is transferred to the string vs how much is used to propel the hammer into the backcheck, that is influenced by several factors more important than resilience, including the mass and compliance (inverse of stiffness) of both the hammer and the spring.  The example of the ball rebounding from the pavement illustrates an extreme, where the ball is light and compliant, the pavement is massive and stiff.  Heavy hammers transfer more energy to strings than light hammers.

hope that helps

Mike


----- Original Message ----- 
From: Isaac OLEG 
To: Pianotech
Sent: 4/23/2004 2:46:01 AM 
Subject: RE: Acetone


So the resilience may be adapted in regards of  the hardness, the weight and also the resilience of the object that is contacted , Indeed if the ball rebound, that mean the energy get reflected to the ball. In the hammer we want some to be given to the strings as well is not it ?

Best

Isaac OLEG

-----Message d'origine-----
De : pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]De la part de Erwinspiano@aol.com
Envoyé : vendredi 23 avril 2004 00:30
À : pianotech@ptg.org
Objet : Re: Acetone


In a message dated 4/21/2004 10:58:19 PM Pacific Standard Time, Richard.Brekne@grieg.uib.no writes:
btw... Whats Delwins take on hammers and laquer ?  Seem to remember he 
went further then we do over here for the natural  hammer resiliancy 
side.  No... this is one of those typical <<opinions vary>> 
questions....and so it should be :)

Cheers Dale !

RicB
  Ric
  Right you are.! It all depends on whos defining resieliency Know what I mean. A steel ball is the most reslient when bounced off cement.  It probaly expends the least amount of energy per bounce than the super ball or a felt hammer.
  Cheers back at ya
  Dale
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