Calculating Time

• The formula for average speed can be rearranged to calculate time taken:

• This can be abbreviated as:

• The units for time will depend on the units for average speed.

• If speed is measured in metres per second (m/s), the units for time will be seconds (s).

• If speed is measured in kilometres per hour (km/hr), the units for time will be hours (hr).

• The units for speed and distance need to correspond with each other for the formula to work. Therefore, it is sometimes necessary to convert the units given for distance before entering the value into the formula.

• For example, if you are given speed in m/s and distance in km, convert distance from km to m by multiplying by 1000.