Re: fast tires

On 6/17/2025 10:53 AM, Frank Krygowski wrote:

On 6/17/2025 4:53 AM, Roger Merriman wrote:

Frank Krygowski <frkrygow@sbcglobal.net> wrote:

>
(Do they have an actual stone stored away somewhere, like they used to
have an actual kilogram?)
>

It’s not used for technical purposes so probably not! And is a much older
system, so the idea of having the stone that all others must conform to is
unlikely to be a thing.

 Pity! It would be fun to go to a museum and see THE stone!  ;-)
 

They finally got rid of the old Kilogram a few years ago - The last actual physical metric in the SI units catalog.
https://www.bipm.org/en/publications/si-brochure/
"It is defined by taking the fixed numerical value of the Planck constant, h, to be 6.626 070 15 × 10−34 when expressed in the unit J s, which is equal to kg m2 s−1, where the metre and the second are defined in terms of c and ∆νCs."
The old Kilogram (The International Prototype of the Kilogram) is a lump of metal stored in a vault in Paris. Apparently it kept losing weight.
https://iopscience.iop.org/article/10.1088/0026-1394/52/2/310/pdf
"All BIPM working standards and the prototypes reserved for special use have been calibrated with respect to the IPK as part of this campaign. All of them were found to have lower masses than when they were calibrated during the 3rd Periodic Verification. As a consequence, the BIPM ‘as-maintained’ mass unit in 2014 has been found to be offset by
35 µg with respect to the IPK."
Hey, we could be measuring in Slugs....
http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/slug.html