Which statement expresses Newton's Third Law?

Which statement expresses Newton's Third Law?

• A. Energy cannot be created or destroyed
• B. For every action there is an equal and opposite reaction
• C. Momentum is conserved
• D. Force equals mass times acceleration

Answer: (B)

Newton's Third Law is about action-reaction forces: forces come in pairs that are equal in strength and opposite in direction. When one object pushes on another, the second object pushes back on the first with the same force in the opposite direction. This is why the statement “for every action there is an equal and opposite reaction” captures the idea perfectly. Think of pushing against a wall: your hand exerts a force on the wall, and the wall exerts an equal and opposite force on your hand. That same paired idea shows up in many situations, like jumping off a boat (the boat is pushed backward as you push the water/boat forward) or a rocket’s thrust (hot gas pushes backward, while the rocket is pushed forward). This principle is distinct from energy conservation (energy cannot be created or destroyed), momentum conservation (the total momentum of a system remains constant in the absence of external forces), or F = ma (which relates force, mass, and acceleration for a single object).

Newton's Third Law is about action-reaction forces: forces come in pairs that are equal in strength and opposite in direction. When one object pushes on another, the second object pushes back on the first with the same force in the opposite direction. This is why the statement “for every action there is an equal and opposite reaction” captures the idea perfectly.

Think of pushing against a wall: your hand exerts a force on the wall, and the wall exerts an equal and opposite force on your hand. That same paired idea shows up in many situations, like jumping off a boat (the boat is pushed backward as you push the water/boat forward) or a rocket’s thrust (hot gas pushes backward, while the rocket is pushed forward).

This principle is distinct from energy conservation (energy cannot be created or destroyed), momentum conservation (the total momentum of a system remains constant in the absence of external forces), or F = ma (which relates force, mass, and acceleration for a single object).