What is the best definition of a 'trajectory' in relation to firearms?

The best definition of 'trajectory' in relation to firearms is the curved path of the projectile after it leaves the barrel. This definition encompasses the essential concept of how a bullet or projectile moves through the air under the influence of gravity and other forces.

When a bullet is fired, it does not travel in a straight line to the target; instead, its trajectory is influenced by factors such as the angle of elevation, the speed at which it was fired, wind resistance, and gravitational pull. The path is typically parabolic, meaning it rises to a peak and then falls as it approaches the target. Understanding trajectory is crucial for accurate shooting, as it helps shooters anticipate where their shots will land based on various conditions and distances.

In contrast, the other options do not comprehensively capture the dynamic nature of projectile motion, focusing instead on aspects like target location or impact, which are only relevant after the projectile has followed its trajectory.