A projectile is an object upon which the only force acting
is gravity. There are a variety of examples of projectiles: an object dropped
from rest is a projectile (provided that the influence of air resistance is
negligible), an object thrown vertically upwards is a projectile
(provided that the influence of air resistance is negligible), and an object
thrown upwards at an angle is also a projectile (the same assumption).
A projectile is any object which,
once projected, continues its motion by its own inertia and is influenced only
by the downward force of gravity.
By definition, a projectile has only one force acting upon
- the force of gravity. If there were any other force acting upon an object,
then that object would not be a projectile. Projectiles can be launched
both horizontally and vertically, and they have both horizontal and vertical
velocity and horizontal and vertical displacement.