Force is a Vector Quantity. A vector quantity is one that requires both a magnitude (size/amount) and a direction for its complete description. Force perfectly satisfies this condition — you must specify not just how much force, but also in which direction it acts.
The SI unit of Force is the Newton (N), where 1 N = 1 kg·m/s². It is named in honour of Sir Isaac Newton.
Consider pushing a book on a table. If you push it with 10 Newtons of force:
This proves direction is essential to describe force, making it a vector.
| Property | Scalar | Vector |
|---|---|---|
| Description | Magnitude only | Magnitude + Direction |
| Examples | Mass, Speed, Temperature, Time | Force, Velocity, Displacement, Acceleration |
| Notation | Simple number (e.g., 5 kg) | Arrow or bold (e.g., F) |
Addition rule: Scalar quantities are added by simple arithmetic. Vector quantities must be added using the Triangle Law or Parallelogram Law of Vector Addition.
Weight is a **vector quantity**. Weight is the gravitational force acting on a body (W = mg), and since force is a vector, weight is also a vector that always points vertically downward toward the center of the Earth.
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