Kaplan Nursing Entrance Practice Exam

Which law explains the slight recoil of a weapon when it is fired?

1. Law of Inertia

2. Newton's Second Law of Motion

3. Newton's Third Law of Motion

4. Law of Universal Gravitation

The correct answer is: Newton's Third Law of Motion

The slight recoil of a weapon when it is fired is explained by Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. When a gun is fired, the rapidly expanding gases produced by the ignited gunpowder push the bullet forward out of the barrel. Simultaneously, there is an equal and opposite force that pushes the gun backward, resulting in the recoil that is felt by the shooter. This principle illustrates the interaction between the bullet and the firearm: as the bullet is forced forward, the firearm experiences a backward force. Understanding this law is crucial in both physics and practical applications, such as firearms training and safety, as it helps explain how and why a weapon behaves during discharge. In contrast, the law of inertia focuses on the tendency of objects to resist changes in their state of motion, while Newton's Second Law relates to the relationship between force, mass, and acceleration. The Law of Universal Gravitation, on the other hand, deals with the attraction between masses due to gravity, which is not applicable to the recoil experienced when firing a weapon.