# Measurement

## Quantity

###### Quantity

A thing that can be measured and shows the result in number

A. Basic Quantity

The basic quantity is independent physical quantities that are not possible to be expressed in terms of any other physical quantity. These quantities are used to derive all other physical quantities.

\begin{array}{cccc} \color{blue}\text{No} && \color{blue}\text{Basic Quantity} &&\color{blue} \text{SI unit} &&\color{blue}\text{Unit Symbol}\\\\ 1&& \text{Length} && \text{meter} && \text{m}\\\\ 2&& \text{Mass} && \text{kilogram} && \text{kg}\\\\ 3&& \text{Time} && \text{second} && \text{s}\\\\ 4&& \text{Electric current} && \text{ampere} && \text{A}\\\\ 5&& \text{Temperature} && \text{kelvin} && \text{K}\\\\ 6&& \text{Amount of substance} && \text{mole} && \text{mol}\\\\ 7&& \text{Luminous intensity} && \text{candela} && \text{cd} \end{array}

B. Derived Quantity

A quantity that is derived from a basic quantity

\begin{array}{cccccc} \color{blue}\text{No} & \color{blue}\text{Derivative Quantity} &\color{blue} \text{Symbol} & \color{blue}\text{Physical Formula}&\color{blue} \text{SI Unit} &\color{blue} \text{Derived From}\\\\ 1&\text{Area}&\text{A}&\text{Length}\times \text{Breadth}&\text{m}^2&\text{length}\\\\ 2&\text{Volume}&\text{V}&\text{Length}\times \text{Breadth}\times \text{Height}&\text{m}^3&\text{length}\\\\ 3&\text{Speed}&v&\dfrac{\text{Distance}}{\text{Time}}&\text{ms}^{-1}&\text{length and time}\\\\ 4&\text{Velocity}&v&\dfrac{\text{Displacement}}{\text{Time}}&\text{m.s}^{-1}&\text{length and time}\\\\ 5&\text{Acceleration}&a&\dfrac{\text{Velocity}}{\text{Time}}&\text{m.s}^{-2}&\text{length and time}\\\\ 6&\text{Density}&\rho&\dfrac{\text{Mass}}{\text{Volume}}&\text{kg.m}^{-3}&\text{mass and length}\\\\ 7&\text{Frequency}&f&\dfrac{\text{Number of Waves}}{\text{Time}}&\text{s}^{-1}\text{ or } \text{Hz}&\text{time}\\\\ 8&\text{Force}&\text{F}&\text{Mass}\times\text{Acceleration}&\text{kg.m.s}^{-2}&\text{mass, length & time}\\\\ 9&\text{Work}&\text{W}&\text{Force}\times \text{Displacement}&\text{kg}.\text{m}^2.\text{s}^{-2}&\text{mass, length & time}\\\\ 10&\text{Power}&\text{P}&\dfrac{\text{Work}}{\text{Time}}&\text{kg}.\text{m}^2.\text{s}^{-3}&\text{mass, length & time}\\\\ 11&\text{Electric Charge}&\text{Q}&\text{Electric Current}\times\text{Time}&\text{A}.\text{s}\text{ or } \text{C}&\text{electric current & time}\\\\ 12&\text{Electric Potential Difference}&\text{V}&\dfrac{\text{Potential Energy}}{\text{Charge}}&\text{kg}.\text{m}^2.\text{s}^{-3}.\text{A}^{-1}&\text{mass, length, time & electric current}\\\\ 13&\text{Pressure}&\text{P}&\dfrac{\text{Force}}{\text{Area}}&\text{kg}.\text{m}^{-1}.\text{s}^{-2}\text{ or } \text{Pa}&\text{mass, length & time}\\\\ 14&\text{Electrical Capacitance}&\text{C}&\dfrac{\text{Charge Stored}}{\text{Potential difference}}&\text{s}^4.\text{A}^{2}.\text{m}^{-2}.\text{kg}^{-1}\text{ or } \text{Farad}&\text{time, electric current, length & mass}\\\\ 15&\text{Impulse}&\text{I}&\text{Force}\times \text{Time}&\text{Kg}.\text{m}^{2}.\text{s}^{-1}\text{ or } \text{N.s}&\text{mass, length & time}\\\\ 16&\text{Momentum}&\text{p}&\text{Mass}\times \text{Velocity}&\text{Kg}.\text{m}^{2}.\text{s}^{-1}\text{ or } \text{N.s}&\text{mass, length & time}\\\\ 17&\text{Torque}&\tau&\text{Force}\times{\text{Distance}}&\text{Kg}.\text{m}^{2}.\text{s}^{-2}\text{ or } \text{N.m}&\text{mass, length & time}\\\\ \end{array}

C. Quantity Based On Its Direction

\begin{array}{cc} \color{blue}\text{Scalar Quantity}&&\color{blue}\text{Vector Quantity}\\\\ \text{A quantity that is stated by numbers}&&\text{A quantity that is stated by numbers and direction}\\\\\\ \text{Example: length, mass, time, temperature, Area, speed}&&\text{Example: displacement, velocity, acceleration, force}\\ \text{density, pressure, work, energy, power, charge}&&\text{weight, impulse, momentum, torque} \end{array}