大象传媒

Vector quantities

Vector quantities have both and an associated direction. This makes them different from scalar quantities, which just have magnitude.

Examples of vector quantities

Some examples of vector quantities include:

  • force 鈥 eg 20 newtons (N) to the left
  • weight 鈥 eg 600 newtons (N) downwards
  • displacement 鈥 eg 50 kilometres (km) east
  • velocity 鈥 eg 11 metres per second (m/s) upwards
  • acceleration 鈥 eg 9.8 metres per second squared (m/s2) downwards
  • momentum 鈥 eg 250 kilogram metres per second (kg m/s) south west

The direction of a vector can be given in a written description, or drawn as an arrow. The length of an arrow represents the magnitude of the quantity. If one arrow is twice as long as another, it represents a force which has twice the magnitude.

The diagrams show three examples of vectors, drawn to different scales.

Three different arrows pointing in different directions,聽the first聽to the left 20 N,聽another to the right labelled 50 km and the third pointing downwards, labelled 9.8 m/s2.