Introduction In physics, we describe the world using physical quantities —measurable properties like length, mass, time, and temperature. These quantities form the language of physics. What Are Physical Quantities? A physical quantity is any property of a material or system that can be measured or calculated. For example: Length (meter) Mass (kilogram) Time (second) Temperature (kelvin) Types of Physical Quantities Base Quantities These are fundamental and independent. There are seven: Length (m) Mass (kg) Time (s) Temperature (K) Electric current (A) Amount of substance (mol) Luminous intensity (cd) Derived Quantities These are formed by combining base quantities using mathematical operations. Examples: Speed = distance/time (m/s) Force = mass × acceleration (N) Scalar and Vector Quantities Scalars : Have magnitude only (e.g., speed, mass). Vectors : Have magnitude and direction (e.g., velocity, force). Concl...