Distance, speed and acceleration

• Terms describing the motion of a body

  • Stationary
  • Constant speed or velocity
  • Accelerating
  • Decelerating
• Velocity


  The speed in a specific direction
• Calculating speed (or velocity)

  Speed (m/s) = distance (m) / time (s)
• Calculating acceleration (or deceleration)

  Acceleration (m/s^2) = change in velocity (m/s) / time (s)
• Motion is described using distance-time graphs and velocity-time graphs
• Motion described by graphs

  • Stationary
  • Constant speed
  • Acceleration
  • Deceleration
• Total stopping distance


  Thinking distance + Braking distance
• Thinking distance


  • The distance travelled between seeing the hazard and braking
• Braking distance


  • The distance the car travels whilst braking
• Factors affecting stopping distance

  • Speed
  • Alcohol or drugs
  • Tiredness
  • Mobile phones
  • Road conditions (e.g. rain)
  • Mass of the car
  • Condition of the brakes
  • Condition of the tyres
• The distance travelled can be calculated by calculating the area under the line of the velocity-time graph
• The acceleration or deceleration can be calculated by calculating the gradient of the line on the velocity-time graph