Final answer:
The shape of a position-time graph for an object in free fall motion from a cliff is a parabolic curve sloping downward, reflecting the acceleration due to gravity.
Step-by-step explanation:
The correct answer for the shape of a position-time graph for an object in free fall motion from the top of a cliff is D. A parabolic curve sloping downward. This is because the object accelerates due to gravity as it falls, resulting in an increase in velocity with time. Consequently, the position-time graph will show a parabolic shape since the position changes at an increasing rate over time, reflecting the constant acceleration due to gravity. Comparing to other examples, for situations without acceleration or constant speed as seen in the bee and hockey puck examples, the graphs are straight lines with negative or positive slopes, showing a linear relationship between the position and time. The situation of the ball launched with an initial horizontal velocity also results in a parabolic trajectory, but the vertical acceleration graph is a horizontal line at a negative value because gravity is a constant downward force. For a falling skydiver before reaching terminal velocity, the graph of the magnitude of displacement versus time would be curved, reflecting increasing velocity. Once terminal velocity is reached, the skydiver falls at constant speed, and the graph becomes a straight line with positive slope. Likewise, the velocity versus time graph would initially be a straight line with positive slope (while accelerating), before leveling off at a constant value once terminal velocity is achieved.