|MadSci Network: Physics|
This concerns the web page: http://www.eeel.nist.gov/811/elec-kilo.html This describes the "electronic kilogram" project, whose purpose is to develop a viable means of deriving the SI-standard kilogram from fundamental laws of physics, instead of simply defining a specific block of metal as representing a mass of one kilogram. The drawing on this page is very sparse on details, and I would like to know how this apparatus works. I'd especially like to know: * The description says that mechanical force is used to counteract gravity on a test mass. However, acceleration due to gravity is not a fundamental law of physics; there must be some way it falls out of the picture, but how? * The apparatus converts electrical energy into mechanical energy. For physicist-quality precision, this conversion must be totally lossless, so how is this achieved? * What is actually being measured? Since all SI units of electricity are derived using the kilogram, I assume the apparatus does not measure electricity. * What will be the form of the new definition, i.e., how will we complete the statement: "A kilogram is that quantity of mass such that ..."?
Re: How does NIST's electronic kilogram apparatus work?
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