Final answer:
The accelerations of the balls are equal in magnitude and directed downwards immediately after release, due to gravity being the only force acting on them.
Step-by-step explanation:
To compare the accelerations of the balls immediately after they leave the thrower's hand, we must recognize that once the balls are in the air and not in contact with any other object, the only acceleration acting on them is due to gravity. This acceleration is directed downwards towards the center of the Earth and has a constant magnitude of approximately 9.8 m/s², regardless of the motion of the ball beforehand or the fact that different balls might have different masses. Therefore, the magnitudes of the accelerations are equal, and the acceleration is always directed downward. The correct answer to the student's question is: No, the magnitudes are equal.