Newton's Third Law of Motion

1. Understanding Newton's Third Law

• For every action force, there is an equal and opposite reaction force.
• These force pairs:
  • Are equal in magnitude.
  • Act in opposite directions.
  • Act on different objects (so they do not cancel each other out).

3. Mathematical Representation

• If object A exerts a force on object B, then: $\vec{F}_{A \text{ on } B} = -\vec{F}_{B \text{ on } A}$

• The negative sign indicates that the forces act in opposite directions.

4. Key Takeaways

• All forces come in pairs.
• The reaction force acts on a different object than the action force.
• Equal but opposite forces do not cancel out because they act on different objects.