Which are the correct examples of Newton’s 3rd law of motion?
(A) Recoil of a gun
(B) When a running horse stops suddenly, the rider bends forward
(C) Motion of a rocket
(D) It gives the definition of force
(E) Swimming
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (C) and (E) only
Newton’s third law says that to every action there is an equal and opposite reaction: when one body pushes another, the second pushes back on the first with an equal force in the opposite direction.
(A) Recoil of a gun Correct. The gun pushes the bullet forward and the bullet pushes the gun back with an equal force, so the gun recoils.
(B) When a running horse stops suddenly, the rider bends forward Incorrect. The rider’s body tends to keep moving after the horse stops; this is inertia of motion, Newton’s first law.
(C) Motion of a rocket Correct. The rocket pushes hot gases out backwards and the gases push the rocket forward.
(D) It gives the definition of force Incorrect. This describes a law, not an example of action and reaction, and the law that defines force is the first law (a force is what changes a body’s state of rest or motion).
(E) Swimming Correct. The swimmer pushes the water backwards and the water pushes the swimmer forward.