Projectile motion is defined as the motion of an object that is thrown or projected into the air and then allowed to move under the influence of gravity alone.

Here's why an object thrown at an angle exhibits projectile motion:

* Initial Velocity: The object has an initial velocity with both horizontal and vertical components.

* Gravity's Influence: The only force acting on the object once it's thrown is gravity, which acts vertically downward. This causes the object's vertical velocity to change, while its horizontal velocity remains constant (neglecting air resistance).

* Parabolic Trajectory: The combination of the initial velocity and the constant downward acceleration due to gravity results in a curved path called a parabola.

Important Note: This assumes we're neglecting air resistance. In reality, air resistance can affect the object's trajectory, making it deviate from a perfect parabola.