Final answer:
A projectile is an object projected through the air, and its path is known as its trajectory, with gravity being the primary force acting on it. Two-dimensional projectile motion is considered for objects such as footballs, where air resistance is often negligible.
Step-by-step explanation:
In physics, the motion of athletes or objects that are projected through the air, subject to only the acceleration due to gravity, is known as projectile motion. These athletes or objects are called projectiles, and their pathway through space is referred to as their trajectory.
Projectile motion can include two-dimensional examples, such as when a football is thrown, where the parabolic path taken by the projectile results from both vertical and horizontal components of motion.
Examples where this concept is applied can be found in a variety of sports and engineering contexts, such as a soccer ball being kicked, a dolphin jumping out of the water, or a parachutist drifting down to Earth.
When considering the forces acting on a projectile, gravity is the only force acting in the vertical direction, while forces like air resistance can affect the projectile horizontally.
However, these are often negligible in theoretical assessments for simplification. This understanding is crucial for calculating trajectories, predicting landing positions, and analyzing motions in physics and engineering fields.