Which principle states that for every action there is an equal and opposite reaction?

Which principle states that for every action there is an equal and opposite reaction?

• A. Newton's Third Law of Motion
• B. The First Law of Thermodynamics
• C. Hooke's Law
• D. Bernoulli's Principle

Answer: (A)

That principle is Newton's Third Law of Motion. It says forces come in action-reaction pairs: when one object pushes on another, the second pushes back with the same strength in the opposite direction. These forces act on two different objects, so they don’t cancel each other out for the whole system. This explains everyday effects like a rocket moving by ejecting gas backward, you generating motion by pushing the ground when you walk, and the recoil you feel when a gun is fired. It’s not about inertia (that’s the first law), nor about energy conservation (thermodynamics), nor about how springs behave (Hooke’s law), nor about fluid dynamics in Bernoulli’s principle.

That principle is Newton's Third Law of Motion. It says forces come in action-reaction pairs: when one object pushes on another, the second pushes back with the same strength in the opposite direction. These forces act on two different objects, so they don’t cancel each other out for the whole system. This explains everyday effects like a rocket moving by ejecting gas backward, you generating motion by pushing the ground when you walk, and the recoil you feel when a gun is fired. It’s not about inertia (that’s the first law), nor about energy conservation (thermodynamics), nor about how springs behave (Hooke’s law), nor about fluid dynamics in Bernoulli’s principle.