What does the law of inertia state concerning firearms?

The law of inertia, which is part of Newton's first law of motion, states that an object at rest will stay at rest and an object in motion will continue to move at a constant velocity in a straight line unless acted upon by an external force. This principle is crucial in understanding the behavior of firearms, particularly regarding the motion of a bullet once it is discharged.

When a firearm is fired, the bullet is propelled forward, and it will continue to travel in that direction until gravitational forces or air resistance act upon it, slowing it down or bringing it to a stop. This concept reinforces the idea that the bullet does not require continuous force to maintain its motion after being fired; it only needs an initial force to set it in motion. The choice accurately captures the essence of inertia as it relates to objects in motion, such as a bullet from a firearm.

The other options misinterpret or oversimplify the concept of inertia. Some suggest limitations on movement that do not align with how inertia operates in physical laws. Inertia applies universally to all objects, regardless of their state of motion or the need for an initial impetus to move.