Final answer:
An object going upwards in free-fall is subject to a constant downward acceleration due to gravity, at 9.80 m/s² on Earth, remaining in effect during the object's entire trajectory.
Step-by-step explanation:
An object going up in free-fall has a downward acceleration. This is because, regardless of the direction of movement, the acceleration due to gravity on Earth remains a constant 9.80 m/s² downward. In physics, when dealing with free-fall motion without air resistance, we consider this acceleration as constant and refer to it as acceleration due to gravity, often represented with the symbol g. Even when an object is thrown upwards and comes momentarily to rest at its highest point before falling back down, this acceleration remains directed down towards the center of the Earth, maintaining the same magnitude.
The definition of the acceleration due to gravity and its effects on free-falling objects are foundational principles in one-dimensional kinematics, an area within physics that explores how objects move. Because the acceleration is consistently downwards, if we define the upward direction as positive in our coordinate system, then acceleration due to gravity (a) would be a = -g = -9.80 m/s². While on its upward journey, the object slows down due to this constant downward acceleration, comes to a temporary stop at the peak of its trajectory, and then accelerates downward as it falls back to Earth.