The Physics
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Opus in profectus

# Distance & Displacement

## Summary

• Distance is a scalar measure of the interval between two locations measured along the actual path connecting them.
• As a scalar it has magnitude only.
• Δs (italic) is the symbol for distance.
• The origin of this symbol is from the Latin word for space: spatium.
• Displacement is a vector measure of the interval between two locations measured along the shortest path connecting them.
• As a vector it must be stated with both magnitude and direction.
• Δr (boldface) is the symbol for displacement.
• The origin of this symbol is from the Latin word for spoke: radius.
• The relation of distance to displacement
• The distance traveled to get from one location to another is always greater than or equal to the magnitude of the displacement between the two locations.

Δs ≥ |Δr|

• Distance approaches the magnitude of displacement as distance approaches zero.  Δs → 0 ⇒ Δs → |Δr|
• The SI unit of distance and displacement is the meter [m].