Hi Philip,
This reminds me of a task I did this morning. I needed to know how heavy a granite block was to figure out how to move it. It was quite simple:
6 dm x 6 dm x 1.5 dm = 54 l
54 l x 2.7 kg/l = 146 kg
This would have been much less simple had I mixed customary units (measured the block in inches) with the density given in metric-only. By the way, my handbook with densities is written and published in the U.S., but is entirely metric aside from the conversion table at the beginning!
J.
Philip S Hall wrote:
Metric is a coherent system purposely designed to be so. Other measures are
not, they have become what they are because they have descended from
disparate applications where they were invented for specific purposes (often
no longer relevent) and subject to regional variations. Hence they are
characterised by a patchwork quilt of unit size ratios after belated
attempts to rationalise them.
