Final answer:
For an object launched horizontally, the acceleration in the y-direction is always 9.8 m/s² downward, represented as ay = -9.8 m/s² when up is positive, while the acceleration in the x-direction is zero.
Step-by-step explanation:
For an object launched horizontally, the acceleration in the y-direction will always be g = 9.8 m/s2, if we define up as the positive direction. This acceleration value is due to the force of gravity, which acts in the vertical direction only. As part of the kinematic equations, ay = -g is used to denote that the acceleration due to gravity is downward, and thus, when the upwards direction is considered positive, the acceleration due to gravity is negative (ay = -9.8 m/s2). In contrast, the acceleration in the x-direction, denoted as ax, is 0 because gravity does not affect the horizontal motion, meaning the object's horizontal velocity remains constant.