> Gene Mechtly wrote in USMA 26509
>> Please note that the SI unit of pressure is newton/meter2, force/area
>> (N/m2, or pascal); kg/cm2 is mass/area which is *not* a pressure.
>> Gene.
And in USMA: 26517 on 2003-08-06 23.26, Joseph B. Reid at
[EMAIL PROTECTED] wrote:
> Quite right. kg/cm2 is a hangover from the
> metre-kilogram(force)-second system that is still used by some
> European engineers. In that system
> force(kilograms) = mass(kilograms) x acceleration / g.
Dear Gene and Joe,
The use of kilogram per square centimetre (or bars) as units of pressure
seem to be hangovers of earlier metric systems. As you say, they are not SI
units. As you deliberate on this issue you might like to ask how many of the
principles of SI are transversed by their use. I have attached a list, of 21
features, below that may help your considerations.
The International System (SI) is universally accepted because:
SI is simple remember SImpleı Starts with SI.
SI is consistent with the decimal numbers we all use.
SI uses the easier to use decimal fractions. There are no vulgar
fractions.
SI calculations can be easily checked with a calculator. By eliminating
vulgar fractions, calculation and conversion errors and costs have been
reduced significantly or eliminated entirely.
SI is based on international standards, not on features that are
peculiar to a particular nation.
SI is the same in all trades and professions.
SI uses standard prefixes to change from smaller to larger units.
SI is coherent; there is no need for conversion factors.
SI is a coherent system symbols are used algebraically like
numbers. There are no illogical inconsistencies.
SI is more logical than any previous methods of measurement. There are
only seven base units in SI, and all other units are derived from these
seven units.
SI uses the seven base units to form all of the derived units that are
needed by all of the worldıs people in all the worldıs occupations.
SI has only one unit for each physical quantity. No conversions are
necessary.
SI has no conversion factors to memorise; there arenıt any.
SI does not use long rows of zeroes to give place value; SI prefixes
eliminate them.
SI is a fully maintained world standard maintained by international
treaty; there are no international differences.
SI uses various internationally approved conventions that govern the
use of terms and symbols.
SI style is used internationally when expressing measured quantities.
This ensures global uniformity in the adoption of SI.
SI units can provides additional information; for example, the number
of molecules of each compound present in a biological fluid is reported by
using the mole.
SI diminishes or completely eliminates measuring confusion.
SI provides a coherent system of units.
SI ensures that quantities and units are uniform in concept and style.
