Final answer:
The ball will not return to the smokestack if shot from a moving train, whether the train is moving at a constant speed or gaining speed. The same applies if the train is moving on a circular track. The horizontal motion of the train and the centrifugal force in the case of the circular track affect the ball's trajectory.
Step-by-step explanation:
In the case of the stationary toy train, the steel ball shot into the air by the spring gun falls back into the smokestack because the train is not moving horizontally. However, if the train is moving at a constant speed along a straight track, the ball will not return to the smokestack. This is because the horizontal motion of the train will affect the ball's trajectory.
If the train gains speed along the straight track, the ball will still not return to the smokestack. As the train gains speed, it causes the ball to deviate even further from its initial path and the ball will fall outside the trajectory of the smokestack.
If the train moves at a constant speed on a circular track, the ball will still not return to the smokestack. This is because the ball will experience a centrifugal force due to the circular motion of the train, which will cause it to move away from the center of the circular track.
Your answers differ because the horizontal motion of the train and the centrifugal force in the case of the circular track affect the trajectory of the ball, causing it to deviate from the smokestack's path.