Which statement best describes Newton's Third Law?

Which statement best describes Newton's Third Law?

• A. An object in motion stays in motion unless acted on by a force
• B. Force equals mass times acceleration
• C. Energy cannot be created or destroyed
• D. For every action, there is an equal reaction

Answer: (D)

Newton's Third Law shows that forces come in paired actions when two objects interact. The force one object exerts on the other is exactly equal in magnitude and opposite in direction to the force the second object exerts back on the first. These action-reaction forces occur at the same time and act on different objects, so they don’t cancel each other out. This is why pushing off the ground propels you forward, or why a rocket’s exhaust pushes backward and the rocket moves forward. The other statements describe different ideas (inertia, F = ma, and conservation of energy) and do not capture this paired-force relationship.

Newton's Third Law shows that forces come in paired actions when two objects interact. The force one object exerts on the other is exactly equal in magnitude and opposite in direction to the force the second object exerts back on the first. These action-reaction forces occur at the same time and act on different objects, so they don’t cancel each other out. This is why pushing off the ground propels you forward, or why a rocket’s exhaust pushes backward and the rocket moves forward. The other statements describe different ideas (inertia, F = ma, and conservation of energy) and do not capture this paired-force relationship.