SI units and conversion factors
SI base units, prefixes, and conversion factors keep physical quantities consistent.
Guess first. It doesn't count.
If 1 meter equals 100 centimeters, which is the same length as 2 meters?
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What you'll learn4 ideas
- SI is an internationally shared measurement system; its base units include the meter for length, kilogram for mass, and second for time.
- Prefixes change unit size: kilo means 1,000, centi means one hundredth, and milli means one thousandth.
- A conversion factor is a fraction of equal measurements, so multiplying by it changes the unit without changing the measurement.
- Choose the factor that cancels the starting unit, and convert measurements to the same unit before adding or comparing them.