Physical Quantities and Their Units 

Prepared by: Maria Johanna Baguio Testa

Physical (กายภาพ) quantities – are quantities (number) (ปริมาณ) that can be measured (วัด).

For Example: length, mass, time, temperature, electric current, light intensity, volume and many others.

Physical Quantities and Their Units

Length, Mass. Time, Temperature:

Length - is a measure (วัด) of distance (ระยะทาง). Unit is meter.

Example: 

Length, Mass. Time, Temperature:

  • Mass (มวล) - is both a property of a physical body and a measure of its resistance to acceleration when a net force is applied. 

       Mass is a measure of the amount of matter in a substance or an object.

       Example: 

            1 kilogram

            500 grams

  • Time - is defined by its measurement: time is what a clock reads.

        Example: 

           1 hour

           6 minutes

           3 seconds

  • Temperature - is a measure of the average kinetic energy of the particles in a system. (how cold or how hot the object is)

       Example: 

          100 Kelvin, k

          60 degree Celsius

          10 Fahrenheit

  • Electric Current  - is the rate of flow of electric charge past a point or region. An electric current is said to exist when there is a net flow of electric charge through a region. Electric charge is carried by charged particles, so an electric current is a flow of charged particles.

       Example: 

       Ampere 

 

THE STANDARD INTERNATIONAL UNIT (SI unit)

 

Prefixes - are used in the SI unit to state a very small or a very big value.

                is added to a unit to change the value of the unit.

Example:  Meter (gigameter, megameter, kilometer, decimeter, micrometer)

                Grams (gigagrams, megagrams, kilograms, nanogram)

Example of units:  meter, gram, second (Prefix + unit)

Example:

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