Units, Physical Quantities, and Vectors (1.1-1.5) - Vocabulary Flashcards

Vocabulary flashcards covering SI basics, base and derived quantities, common units, unit prefixes, significant figures, and unit consistency as presented in the notes.

SI (International System of Units)

The internationally adopted system of units used in science and engineering; standard set of base units for physical quantities.

MKS system

Another name for SI, emphasizing meter (Length), kilogram (Mass), and second (Time) as base units.

Meter

SI unit of length; defined as the distance light travels in vacuum in 1/299,792,458 of a second.

Kilogram

SI unit of mass; defined by a specific cylinder kept at the International Bureau of Weights and Measures (in France).

Second

SI unit of time; currently defined by the frequency of cesium-133 atomic transitions (9,192,631,770 cycles per second).

Basic quantities

Fundamental quantities in mechanics, such as length, mass, and time.

Derived quantities

Quantities formed by combining basic quantities (e.g., velocity, area) and their units.

Length

One of the fundamental quantities; measured in meters in SI.

Mass

One of the fundamental quantities; measured in kilograms in SI.

Time

One of the fundamental quantities; measured in seconds in SI.

Pound (lb)

Unit of mass; 1 lb = 0.4535 kg.

Ounce (oz)

Unit of mass; 1 oz = 0.0283 kg.

Ton

Unit of mass; 1 ton = 910 kg (as given in the notes).

Slug

Unit of mass used in English engineering units; 1 slug = 14.59 kg.

Nanometer (nm)

Unit of length equal to 1 × 10^-9 meters.

Micrometer (μm)

Unit of length equal to 1 × 10^-6 meters.

Millimeter (mm)

Unit of length equal to 1 × 10^-3 meters.

Centimeter (cm)

Unit of length equal to 1 × 10^-2 meters.

Kilometer (km)

Unit of length equal to 1 × 10^3 meters.

Significant figures

Digits that carry meaning about the precision of a measurement; include all certain digits plus the first uncertain digit.

Leading zeros

Zeros at the beginning of a number; they do not count as significant figures.

Captive zeros

Zeros between significant digits; they are significant.

Trailing zeros with a decimal point

Zeros at the end of a number after a decimal point; they are significant.

Rules for multiplication and division (significant figures)

The result cannot have more significant figures than the factor with the fewest significant figures.

Rules for addition and subtraction (decimal places)

The result should have the same number of decimal places as the quantity with the fewest decimal places.

Unit consistency

An equation must be dimensionally consistent; carry units through calculations and convert to standard units as needed.

Atomic clock

A clock that uses the cesium-133 frequency to keep time, forming the basis for the second.

Speed conversion (example)

Converting a speed value between units (e.g., from km/h to m/s) using standard conversion factors.