Final answer:
Acceleration can be represented graphically on a velocity-time graph, where a straight line indicates constant acceleration and a curved line indicates changing acceleration.
Step-by-step explanation:
An acceleration line refers to the graphical representation of acceleration over time in a velocity-time graph. When the acceleration is constant, the velocity-time graph produces a straight line, indicative of uniform acceleration. This is because the slope of the line, which represents acceleration, does not change when plotted against time. Conversely, when acceleration is changing, the velocity-time graph will be curved, showing a non-uniform acceleration. In this case, the slope of the tangent to the curve at any point represents the instantaneous acceleration at that time.
To calculate acceleration from a velocity-time graph, we use the concept that slope is rise over run; on such a graph, the rise is the change in velocity (Δv), and the run is the change in time (Δt). If the graph is a straight line, it reveals that the acceleration is constant over the time interval considered. Understanding these relationships is essential for analyzing motion and making predictions about the behavior of moving objects.