Purpose: To explore and predict the motion of projectiles in two dimensions using computer
Background: Projectile motion refers to the motion of an object that experiences no forces
other than a constant gravitational force. This means that air resistance must be insignificant
enough to be ignored, and that the object must not change its altitude very dramatically (in this
case, “very dramatically” means many kilometers of altitude), since the strength of the local
gravitational field changes with distance from the Earth’s center.
Real projectiles on Earth always experience some amount of air resistance, but projectile
motion’s assumption of zero air resistance is often a good approximation, and serves as a
starting point for analyzing the motion of launched, thrown, or dropped objects.
For projectiles which land at the same height they are launched from, the horizontal
displacement (referred to as range) is determined by three parameters: Initial speed v0, launch
angle ? (this is the angle between the initial velocity vector and the horizontal), and the local
gravitational acceleration g. The range R is given by the following equation: