2.3 Newton’s Third Law

• What does Newton's Third Law state?

  Every action has a reaction
• Action and reaction forces act on the same object.

  False
• Action and reaction forces act in opposite directions
• What is the reaction force to the force exerted by one object on another?

  Force exerted by the second object on the first
• What is the magnitude of the reaction force if the action force is 50 N?

  50 N
• Match the features with action or reaction forces:

  Object ↔️ Acts on one object

  Magnitude ↔️ Equal

  Direction ↔️ Opposite

  Simultaneity ↔️ Occur simultaneously
• In the example of pushing a wall, the action force is the force of hands on the wall
• Action and reaction forces act on different objects simultaneously.

  True
• What is the fundamental principle of Newton's Third Law?

  Every action has equal reaction
• The action and reaction forces have the same direction.

  False
• Match the action-reaction forces in everyday examples:

  1️⃣ Person walking

  2️⃣ Force of foot pushing ground backward ||| Force of ground pushing foot forward

  3️⃣ Pushing a door

  4️⃣ Force of hand on door ||| Force of door on hand

  5️⃣ Ball bouncing

  6️⃣ Force of ball on floor ||| Force of floor on ball
• The magnitude of the action force is equal to the magnitude of the reaction force.
• What is the first step in applying Newton's Third Law to solve physics problems?

  Identify force pairs
• The reaction force in Newton's Third Law acts in the same direction as the action force.

  False
• The action and reaction forces are always equal in magnitude and opposite in direction.


  True
• Newton's Third Law states that for every action force, there is an equal and opposite reaction force.


  True
• What is the magnitude relationship between action and reaction forces?

  Equal
• Match the example with the corresponding action and reaction forces:

  Person walking ↔️ Force of foot pushing ground backward

  Pushing a door ↔️ Force of hand on door

  Ball bouncing ↔️ Force of ball on floor
• The action force acts on one object, while the reaction force acts on the second
• What is the key principle of Newton's Third Law regarding action and reaction forces?

  Equal and opposite
• When you push against a wall, the reaction force is the force of the wall pushing back on your hands.


  True
• Equilibrium occurs when the net force on an object is zero.


  True
• While Newton's Third Law describes action and reaction forces, equilibrium describes a state where the net force on an object is zero
• The action-reaction principle explains that forces are equal in magnitude
• What is the relationship between the magnitudes of action and reaction forces?

  Equal
• On what do action and reaction forces act?

  Different objects
• Action and reaction forces are equal in magnitude but act in opposite directions.

  True
• The reaction force to an action force always acts on the first
• The action-reaction principle underlies the forces between interacting objects.


  True
• Why do action and reaction forces not cancel each other out?

  They act on different objects
• What is the reaction force to a bird's wings pushing air down?

  Force of air pushing bird up
• What are the four key features of action and reaction forces?

  Object, magnitude, direction, simultaneity
• The action force acts on one object
• Why do action and reaction forces not cancel each other out?

  Act on different objects
• What ensures that interacting forces in Newton's Third Law are equal in magnitude but opposite in direction?

  Every action has equal reaction
• Action and reaction forces occur simultaneously as a pair.


  True
• In the example of a person pushing against a wall, the reaction force is the force of the wall pushing back on the person's hands.
• What is the reaction force when a rocket expels exhaust gases downward?

  Ground pushes rocket upward
• What is a key characteristic of action and reaction forces according to Newton's Third Law?

  Equal and opposite
• The action force acts on one object, while the reaction force acts on the second