Speed=Distance/Time

Key Stage 3

Meaning

This equation triangle shows how to rearrange the equation to find speed, distance or time. To find speed cover over the s to find it is d/t. To find distance cover over the d to find it is s x t. To find time cover over t to find it is d/s.

\[Speed = {\tfrac{distance}{time}} \] is an equation which can be used to calculate the speed of an object given the distance traveled and the time taken to travel that distance.

About Speed=Distance/Time

The standard scientific units for measuring speed are metres per second (m/s).

The units of speed are given by the units of distance used and the units of time used in the calculation.

\[Speed = {\tfrac{distance}{time}} \] \[Speed = {\tfrac{metres}{seconds}} \] \[Speed = {\tfrac{m}{s}} \] \[Speed = m/s \]

Example Calculations

A person jogs 300 metres in 120 seconds. Calculate the speed of the jogger.	A racing car travels 500 metres in 10 seconds. Calculate the speed of the racing car.
distance = 300m time = 120s \(Speed = {\tfrac{distance}{time}} \) \(Speed = {\tfrac{300}{120}} \) \(Speed = 2.5m/s \)	distance = 500m time = 10s \(Speed = {\tfrac{distance}{time}} \) \(Speed = {\tfrac{500}{10}} \) \(Speed = 50m/s \)
A horse takes 20 minutes to trot 2.4 kilometres. Calculate the speed of the horse in metres per second.	The International Space Station takes 92 minutes to orbit the Earth once travelling 42,000 kilometres. Calculate the speed of the ISS.
distance = 2.4km = 2400m time = 20min = 1200s \(Speed = {\tfrac{distance}{time}} \) \(Speed = {\tfrac{2400}{1200}} \) \(Speed = 2m/s \)	distance = 42,000km = 42,000,000m time = 20min = 5400s \(Speed = {\tfrac{distance}{time}} \) \(Speed = {\tfrac{42000000}{5400}} \) \(Speed = 7608.7m/s \) \(Speed \approx 7600m/s \)