Final answer:
The velocity of a dropped ball that is gaining speed cannot be constant, as it is accelerating due to gravity. For a ball launched horizontally, the graph of its vertical acceleration over time shows a constant negative value, indicating a consistent downward acceleration.
Step-by-step explanation:
Free Fall and Vertical Acceleration
When a ball is dropped and gains speed as it falls, its velocity cannot be constant because it is undergoing acceleration due to gravity. In free fall, gravity is the only force acting on the object, causing it to accelerate downwards at a rate of approximately 9.8 m/s2 on Earth. For the experiment described, where a ball is launched with an initial horizontal velocity from a height of 2 meters, its vertical acceleration due to gravity is constant. Therefore, the graph of the ball's vertical acceleration versus time would show a negative value that does not change with time, indicating consistent acceleration (downward)
The vertical acceleration being negative simply means that it is directed downwards when we choose upwards as the positive direction. Regardless of the presence of a horizontal component of motion, vertical acceleration remains constant at -9.8 m/s2 until the ball hits the ground, assuming air resistance is negligible. During its trajectory, no other forces are acting on the ball in vertical direction other than gravity, hence the acceleration does not change.