Hi Sarah, and others. Back from a weekend in the hills and busy getting caught up with P-tech mail. A couple comments below. Sarah Fox wrote: > Hi Ric, > > Cool applet! :-) Anyone using it should be aware that the rotating platform > has mass, else the acceleration of the hanging mass (whatever amount of > mass) would be 9.8 m/s^2 with the platform unloaded. Also, be aware that > the amount of hanging mass is not equivalent to tangential force, but the > two are of course related -- the best approximation occurring when the least > weight is used and the acceleration is the least (i.e. and farthest from the > asymptote of 9.8 m/s^2). Anyway, yes, the applet applies perfectly to the > touchweight issue. Grin... glad you liked it. And thanks for the clarifications. > > >From a static, touchweight perspective, 500 g on the outer perimeter is > equivalent to 1000 g mid-way out on the platform (half the radius). > However, from the perspective of dynamic performance, the 1000 g solution > yields a lower moment of inertia (by half, ignoring the unknown moment of > inertia of the supporting platform) and is therefore capable of greater > rotational acceleration with the same tangential force (similar to finger > pressing down on end of key). (Of course we can't see the full magnitude of > the effect, since the platform has unknown mass. To minimize the > contribution of the platform, place lots of mass on the platform.) Yes... thats sort of how I read the results, tho its going to take me a bit to weed through the refered too maths that explain the moment of interia as described by this site. So let me see if I understand this correctly. Ignoring the moment of inertia for the key, this is shows that for a given FW specification, more leads placed closer to the balance rail pin yeild a lower moment of inertia, and yield greater degrees of acceleration then less lead out towards the end of the key. Yes ? This being the case... then loweing key inertia, and hence increasing key acceleration can be accomplished by concentrating more of whatever key mass is used in the center.. yes again ? If so... what happens to half the argumenation against the accelerated action ? > Thanks for pointing us to this cool virtual demonstration! > > Peace, > Sarah Cheers RicB -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html
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