Welcome to our lesson on projectile motion! Projectile motion is the motion of an object thrown or projected into the air, subject only to the force of gravity. We see this everywhere around us - when shooting a basketball, firing a cannonball, or throwing a ball. Let's explore this fascinating topic together.
To analyze projectile motion mathematically, we need to make some key assumptions. First, we ignore air resistance, which greatly simplifies the calculations. Second, we assume gravity is constant at nine point eight meters per second squared. Third, for short distances, we treat Earth as flat. These assumptions give us the ideal parabolic trajectory shown in blue, while the red curve shows what happens with air resistance in reality.
The most important concept in projectile motion is that horizontal and vertical motions are completely independent. Gravity only acts vertically downward, so it doesn't affect horizontal velocity. This means a ball dropped straight down and a ball projected horizontally from the same height will hit the ground at exactly the same time, even though one travels much farther horizontally.
Now let's analyze the motion components separately. For horizontal motion, there's no acceleration, so horizontal velocity remains constant throughout the flight. The horizontal distance equals initial horizontal velocity times time. For vertical motion, gravity causes constant downward acceleration of nine point eight meters per second squared. The vertical velocity decreases going up and increases going down, following the kinematic equations shown.
To summarize what we have learned about projectile motion: it combines independent horizontal and vertical motions. Horizontal velocity stays constant when we ignore air resistance, while vertical motion follows gravity with constant acceleration. Understanding this independence principle allows us to analyze each component separately and solve complex projectile problems step by step.