Matter, being a body or a substance, and energy can be quantitatively evaluated. Each characteristic that can be quantified constitutes a physical quantity.
Length, mass, temperature, time, volume, strength, amount of matter, etc. These quantities are evaluated by the units of measure adopted by convention and each unit has its symbol.
For example, the m The symbol of the meter. The value of a quantity may be expressed by a number and a unit of measure. Example: 25 ° C, 100m.
Unit of measure systems
A unit group is known as a unit of measure system. The most used is the SI (International System of Units). Note the SI units:
amount of matter
meters per second
m / s