Newton's Third Law Action-Reaction Pair

Steps:

• Newton's third law pairs forces between two interacting objects: equal magnitude, opposite directions.
• Firework pushes gases downward (action force on gases).
• Gases push firework upward with thrust (reaction force on firework).
• Air resistance acts between firework and surrounding air; weight is gravitational.
• Pair must be mutual forces between firework and gases only.

Why C is correct:

• Thrust is the upward reaction on the firework to the downward action force it exerts on the gases, directly from Newton's third law.

Why the others are wrong:

• A: Air resistance acts between firework and air, not paired with force on gases.
• B: Both air resistance and thrust act on the firework alone, not as mutual pair.
• D: Thrust acts between firework and gases; weight is Earth's gravitational pull on firework.

Final answer: C