The movement of a projectile is a movement in two dimensions (forming a curved path: a parabola shape) with <u>constant acceleration. </u>
<u> </u>
A projectile is any body or object that is thrown or projected by means of some force and continues in motion by its own inertia. This means the only force that acts on it while in motion is <u>the acceleration of gravity</u> (in this case we are on Earth, so the gravity value is ).
Where gravity influences the <u>vertical movement</u> of the projectile, while <u>the horizontal movement</u> of the projectile is the result of the tendency of any object to remain in motion at a constant speed (according to Newton's 1st law of motion sometimes called Law of Inertia).
The other options are <u>incorrect</u> because are <u>false</u>:
-The forward motion negates air resistance: There is always at least a small percent of air resistance, as long as that movement is done on Earth.
-It has variable acceleration: In projectile motion acceleration is constant (gravity acceleration) .
-It is unaffected by gravity: The only force that acts on the projectile is due gravity.