Final answer:
The highest point of a projectile's flight path is known as the apex, where the vertical velocity is zero. The optimal launch angle to maximize the range on level ground is 45°.
Step-by-step explanation:
When referring to the speed of release, the highest point of the flight path of a projectile is called the apex. This is the point where the vertical component of the projectile's velocity is zero (vy = 0), and it can be calculated using kinematic equations. For example, to find the maximum height y above the starting point, the equation v² = v² - 2g(y - yo) is used. When discussing the optimum angle for launching a projectile to cover the maximum distance, the answer is 45°; at this angle, the projectile achieves the greatest range on level ground, a concept that is commonly addressed in physics education to understand projectile motion and kinematics.