When an object is launched with some initial speed at an angle to the ground, it moves in a parabolic path due to gravity. The object is called the projectile, and the path it follows is called the trajectory. The horizontal distance covered by the projectile is called the Range, whereas the maximum height, the projectile reaches, is known as the zenith of the trajectory. The projectile's motion can be considered independent along the horizontal and vertical directions. Assuming negligible air resistance, the only force acting on the projectile is due to the earth's gravity. So, the vertical component of acceleration, is equal to minus g. The horizontal component of acceleration is zero. So, the projectile maintains a constant horizontal velocity. The vertical component of the velocity, initially decreases, until the projectile reaches the zenith, at which point it becomes zero. It increases again as the projectile follows the downward trajectory. However, the presence of air resists an object's motion, decreasing the horizontal velocity. The object's range and zenith are lesser than the path it would follow in a vacuum.