Fundamental and Derived Quantities

Fundamental

Means basic, or not derived from anything else.

Fundamental Quantities

The basic physical quantities that are defined independently and cannot be expressed in terms of other physical quantities.

Examples of Fundamental Quantities

Length — metre (m)

Mass — grams, or kilogram (g/kg)

Time — seconds, minutes, or hours (s/min/h)

Electric — ampere (A)

Temperature — celsius, fahrenheit, or kelvin (°C/°F/K)

Amount of Substance — moles (mol)

Luminous Intensity — candela (cd)

Derived

Means ”come from” or ”built from” other things.

Derived Quantities

Quantities that are formed by combining fundamental quantities through mathematical relationships like multiplication or division.

Examples of Derived Quantities

Speed — length/time (m/s)

Force — mass × acceleration (kg m/s² or Newton (N))

Area — length × length (m²)

Volume — length × length × length (m³)

Density — mass/ volume (kg/m³)

Metric System

Internationally agreed decimal system of measurement created in France in 1799.

Better known as the International System of Units (SI).

Example of Basic Type of Measurement

Length = meter (m)

Weight = gram (g)

Capacity = liter (L)

Metric Prefixes

Kilo = 1,000

Hecto = 100

Deca = 10

Deci = 1/10

Centi = 1/100

Mili = 1/1,000

English System

Was lawfully accepted for use in the United States in 1866 but not adopted as its official system of measurement.

People use body parts or familiar objects as their measurement.

Example of English System

Foot (shorter distance) = human foot length (12 inches)

Mile (longer distance) = human pace (1,000 paces)

Galloons (capacity) = cups, tablespoon, teaspoon

English to Metric System (Length)

1 in = 2.54 cm

0.39 in = 1 cm

1 ft = 30.48 cm

3.28 ft = 1 m

1 yd = 0.91 m

1.09 yd = 1 m

1 mi = 1.61 km

0.62 mi = 1 km

English to Metric System (Weight)

1 oz = 28.35 g

0.035 oz = 1 g

1 lb = 0.45 kg

2.22 lb = 1 kg

1 ton = 0.91 metric tons

1.10 tons = 1,000 kg