Initial velocity influences the final speed of a projectile at landing, with the final speed equating to the initial speed when neglecting air resistance. Acceleration is positive when the final velocity exceeds the initial velocity. The time a horizontally projected object remains airborne is affected by its initial vertical velocity and projection height. Gravity specifically impacts the vertical components of projectile motion, while vector mechanics can be broken down into various coordinate systems. In the case of a ball kicked at 10 m/s at a 30-degree angle, it will land at the same speed of 10 m/s, as it slows during ascent and accelerates back down.