Scalars & Vectors (Cambridge (CIE) IGCSE Physics): Revision Note

Scalar & vector quantities

Extended Tier Only

• All quantities can be one of two types:

  • A scalar

  • A vector

Scalars

• Scalar quantities have only a magnitude

  • Mass is an example of a scalar quantity because it has magnitude without direction

  • Energy and time are also examples of scalar quantities

Vectors

• Vector quantities have both magnitude and direction

  • Weight is an example of a vector quantity because it is a force and therefore has both magnitude and direction

  • Acceleration and momentum are also examples of vector quantities

Distance and displacement

• Distance is a measure of how far an object has travelled, regardless of direction

  • Distance is the total length of the path taken

  • Distance, therefore, has a magnitude but no direction

  • So, distance is a scalar quantity

• Displacement is the distance between two points in a straight line, in a stated direction

  • So, displacement is a vector quantity

Speed and velocity

• Speed is a measure of the distance travelled by an object per unit time, regardless of the direction

  • So, speed is a scalar quantity

• Velocity is the speed of an object in a given direction

  • So, velocity is a vector quantity

Examples of scalars & vectors

Extended Tier Only

• The table below lists some common examples of scalar and vector quantities

• Corresponding scalars and their vector counterparts are aligned in the table where applicable