Motion

• Speed

  Distance traveled per unit time
• Acceleration

  Change in velocity over time
• The acceleration of free fall near to the Earth is constant
• Calculating average speed

  Total distance / Total time
• Units of measurement

  • mm
  • cm
  • m
  • km
  • ms
  • s
  • minutes
  • hours
• Remember to convert units to make sure everything is equivalent
• Velocity

  Speed in a given direction
• Distance-time graph

  • Gradient is velocity
  • Negative gradient is returning back to the starting point
  • Horizontal line means it is stationary
  • If distance is zero, it is back at the starting point
  • Curved line means velocity is changing and it is accelerating
• Speed-time graph

  • Gradient is acceleration
  • Negative gradient (deceleration) is negative acceleration
  • If speed is zero, it is at rest
  • Horizontal line means constant speed
  • Area under the line is the distance travelled
  • Curved line means acceleration is changing