Our chemistry professor said that "mg for mass, g/m3 for density, ms for time are all SI units".
I want to make sure now, even if we added a prefix to the unit, will it still be an SI unit?
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Sign up to join this communityOur chemistry professor said that "mg for mass, g/m3 for density, ms for time are all SI units".
I want to make sure now, even if we added a prefix to the unit, will it still be an SI unit?
Yes, when prefixes are used with coherent SI units, the resulting units are still SI units; however, they are no longer coherent.
The metre per second, symbol m/s, is the coherent SI unit of speed. The kilometre per second, km/s, the centimetre per second, cm/s, and the millimetre per second, mm/s, are also SI units, but they are not coherent SI units.
kg
is the base unit of mass, not grams. See also unc.edu/~rowlett/units/cgsmks.html: the CGS system (centimeter, gram, second) used to be the base units (with force in dynes for example), but now almost everyone uses MKS (with force in Newtons).
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Sep 30, 2017 at 15:52
kg
. WHY? Why would you ruin an otherwise perfect system? Like, in a system all about logical unit choices, you go and do that. Sigh.
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Sep 30, 2017 at 19:03