Units and Measurement 02 Lecture Notes

Flashcards covering fundamental and derived physical quantities, unit systems, prefixes, and supplementary angular units.

Fundamental Physical Quantities (7)

The seven basic quantities are Mass ($kg$), Length ($m$), Time ($s$), Current ($A$), Temperature ($K$), Amount of Substance ($mol$), and Luminous Intensity ($cd$).

Velocity / Speed

Defined as $\frac{\text{displacement}}{\text{time}}$ or $\frac{\text{distance}}{\text{time}}$, with the derived unit $m/s$.

Acceleration

Defined as $\frac{\text{velocity}}{\text{time}}$ with the derived unit $m/s^2$.

Force (Newton)

Represented by the formula $F = ma$, with the unit $kg\,m/s^2$.

Work (Joules)

Defined by the formula $W = F \cdot \text{displacement}$, with the unit $kg\,m^2/s^2$.

Power (Watts)

Defined as $\frac{\text{Work}}{\text{time}}$, with the unit $kg\,m^2/s^3$.

Micro

An important prefix representing $10^{-6}$.

Nano

An important prefix representing $10^{-9}$.

Pico

An important prefix representing $10^{-12}$.

Femto

An important prefix representing $10^{-15}$.

Angstrom

A unit of length equal to $10^{-10}\,m$.

FPS System

A system of units where Mass is measured in Pounds, Length in Foot, and Time in Seconds.

CGS System

A system of units where Mass is measured in gram, Length in Centimeter, and Time in Second.

MKS System

A system of units where Mass is measured in Kilogram, Length in meter, and Time in Second.

International System of Units (SI)

Consists of the MKS system plus two supplementary units: Plane Angle and Solid Angle.

Plane Angle ($\theta$)

Calculated as $\theta = \frac{\text{Arclength}}{\text{Radius}}$, with the unit radians.

1 Radian

The angle at the center of a circle produced when the arc length is equal to the radius of the circle.

Radian Conversion (180°)

The mathematical relationship where $180^{\circ} = \pi\,rad$.

Minute (1')

A unit of angular measurement where $1^{\circ}$ is divided into $60$ equal parts; $1^{\circ} = 60'$.

Second (1'')

A unit of angular measurement where $1'$ is divided into $60$ equal parts; $1' = 60''$.