Newton’s Third Law

• • Newton's third law of motion states:Whenever two bodies interact, the forces they exert on each other are equal and opposite 
  • The pair of forces exerted by the interacting objects are known as force pairs
• Newton's third law explains the forces that enable someone to walk

  • The foot exerts a push force on the ground
  • The ground exerts a push force force on the foot
  • The forces are equal in magnitude and opposite in direction
• The foot pushes the ground backwards, and the ground pushes the foot forwards. Newton's third law explains the forces that enable people to walk:

  
• • Vector diagrams can be used to represent Newton's third law
• • Use the following three rules to help you identify a third law pair:

  1. The two forces in a third law pair act on different objects
  2. The two forces in a third law pair always are equal in size but act in opposite directions
  3. The two forces are always the same type: weight, normal contact force, etc.