Here's why:
* Gravity is a constant force: It pulls all objects towards the center of the Earth with a nearly constant acceleration of approximately 9.8 m/s².
* Projectile motion: A projectile is an object that is thrown or launched and then continues moving under the influence of gravity alone.
* Vertical acceleration: Since gravity acts vertically downwards, it is the sole force responsible for the vertical acceleration of a projectile.
Important Note: While gravity affects the vertical motion, it does *not* affect the horizontal motion of a projectile in a vacuum. This is why projectiles follow a curved path (a parabola).
