Speed (AQA GCSE Physics: Combined Science)

• The speed of an object is the distance it travels every second
• Speed is a scalar quantity
  • This is because it only contains a magnitude (without a direction)

• The average speed of an object is given by the equation:

• Distance is measured in metres, m
• Time is measured in seconds, s
  • Speed is therefore measured in metres per second, m/s

A hiker might have an average speed of 2.0 m/s, whereas a particularly excited bumble bee can have average speeds of up to 4.5 m/s

• The speed of an object is rarely constant
  • Hikers change their pace continuously as they walk
  • Bumblebees buzz around in all directions with varying speed
  • Cars are constantly speeding up and slowing down throughout a journey

• Non-uniform motion refers to motion that is changing
• Changing motion can mean the object is changing its speed, direction or both

Race drivers know all about non-uniform motion, especially slowing down for corners and speeding up on the straight sections of track