Scalar quantities

A physical quantity is something that can be measured. Scalar quantities only have a magnitude.

Examples of scalar quantities

Some examples of scalar quantities that refer to motion include:

  • distance, eg 19 metres (19 m)
  • speed, eg 8 metres per second (8 m/s)

Adding scalars

Scalar quantities can be added by just adding their values together.

Example

A car increases its speed by 12 m/s when it is already travelling at 6 m/s. Calculate its new speed.

12 + 6 = 18 m/s

Subtracting scalars

Scalar quantities can be subtracted by subtracting one value from another.

Example

A man walks a distance of 350 m. His home is 1000 m away. Calculate how far he needs to walk to get home.

1000 - 350 = 650 m