Forces and motion

• Distance

  • Distance is how far an object moves.
  • Distance does not involve direction.
  • Distance is a scalar quantity
• Displacement

  • Displacement includes both the distance an object moves, measured in a straight line from the start point to the finish point and the direction of that straight line.
  • Displacement is a vector quantity
• Speed

  • Speed does not involve direction.
  • Speed is a scalar quantity
  • The speed at which a person can walk, run or cycle depends on many factors including: age, terrain, fitness and distance travelled
• Typical Values of Speed

  • walking ̴ 1.5 m/s
  • running ̴ 3 m/s
  • cycling ̴ 6 m/s
  • Car~ 10-30 m/s
  • Aeroplane~ 200-250 m/s
  • Sound In Air~330 m/s
• Velocity

  • Velocity of an object is its speed in a given direction.
  • Velocity is a vector quantity