Physical Quantities

Physical Quantities

  1. A physical quantity is a quantity that can be measured. 
  2. A physical quantity can be divided into base quantity and derived quantity. 

Base Quantities

  1. Base quantities are the quantities that cannot be defined in term of other physical quantity.
  2. The 5 base quantities and its units are as in the table below: 
In SPM, you need to remember all five base quantities and their SI unit.
  1. Take note that, the unit of temperature is Kelvin but not Celsius.

Derived Quantities

  1. A derived quantity is a Physics quantity that is not a base quantity. It is the quantities which derived from the base quantities through multiplying and/or dividing them.
  2. For example, speed is defined as the rate of change of distance, Mathematically, we write this as Speed = Distance/Time. Both distance and time are base quantities, whereas speed is a derived quantity as it is derived from distance and time through division.


(Speed is derived from dividing the distance by time.)

Derived Quantities That You Need to Know in SPM

  1. Below are the derived quantities that you need to know in SPM. You need to know the equation of all the quantities so that you can derive their unit from the equation.
  2. If you find it difficult to memorise all these equations, you can skip it now because you are going to learn all of them in the other chapter.