Final answer:
Straight segments on a position-time graph represent constant velocity and therefore indicate zero acceleration, as the rate of velocity change is nonexistent. The correct answer is: C) They indicate zero acceleration.
Step-by-step explanation:
When analyzing a position-time graph with straight segments, these segments indicate the type of acceleration an object is experiencing. Straight segments on a position-time graph represent constant velocity, which implies that the acceleration is zero. Hence, the correct answer is: C) They indicate zero acceleration.
Position-time graphs with straight, diagonal lines imply that the object is moving at a constant velocity - the slope of the line denotes the velocity. If the slope is positive, the object is moving forward; if negative, the object is moving backward. However, the crucial insight is that the linearity of the segment means the velocity is not changing over time; hence the acceleration, which is the rate of change of velocity, must be zero. An acceleration vs. time graph would depict this as a horizontal line at an acceleration value of zero.
A graph depicting positive acceleration would curve upward, showing the velocity increasing over time, while a graph depicting negative acceleration (deceleration) would curve downward, showing the velocity decreasing over time. Large and constant negative acceleration or positive acceleration would appear as straight, non-horizontal lines on an acceleration vs. time graph, indicating that the acceleration is constant but nonzero.
While any of these graphs can display negative values for position, velocity, and acceleration, they should never show negative time, as time is always moving forward.