Motion

Definition of Speed

• Speed is the rate of change of position with respect to time.
• Speed = Distance / Time
• Units: metres per second (m/s)

Calculating Speed

• Use the speed formula: Speed = Distance / Time
• Rearrange to calculate distance or time given the other two variables.
• Example: If a car travels 150 m in 30 s, its speed is 150 m / 30 s = 5 m/s.

Exam Tips

• When calculating speed, ensure you convert units correctly (e.g. km/h to m/s).
• Be able to interpret distance-time graphs to determine speed.