From DT Online
Vectors are Forces which are defined by both magnitude and direction.
Vectors can be represented by lines drawn to scale providing we know:
- the magnitude
- the point of application
- the line of action
- the direction
For example, from any point O as shown, a line can be draw to a scale representing an upward pointing force of 2 newtons and similarly from the same point, a shorter line to represent the downward pointing force of 1 newton.
Common sense tells us in such a simple example that these two opposing forces could be replaced by a single 1 newton. force pointing upwards from point O (i.e. the Resultant) and the point O could be held still by an equal and opposite, downwards pointing 1 newton force (i.e. the Equilibrant).