Units and Standards
There are 4 fundamental scientific measurements:
- Mass
- Length
- Time
- Electric Charge
The following summarizes their basic SI (International Metric System) units:
Fundamental Quantity |
Mass |
Length, distance, |
Time |
Charge |
SI Unit |
kg (kilogram) |
m (metre) |
s (second) |
C (coulomb) |
Symbol |
m |
Δd |
t |
Q |
Scalar vs. Vector Quantities
- Scalar quantities express only a quantity and a unit
- Vector quantities express a quantity, a unit and a direction
Examples:
Quantity | Symbol | Type | Example |
distance | Δd | scalar | Δd = 10 m |
displacement | vector | = 10 m [E] |