# Explore and predict the motion of projectiles in two dimensions using computer simulations….

Purpose: To explore and predict the motion of projectiles in two dimensions using computer

simulations.

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: