WAEC Physics 2021 Paper

Concept:Acceleration describes how quickly an object's velocity changes over time.Explanation:Consider a graph with velocity on the vertical axis and time on the horizontal axis.For any two points on this graph, the slope is the vertical difference divided by the horizontal difference.That gives $\frac{\text{change in velocity}}{\text{time taken}}$, written as $\frac{\Delta v}{\Delta t}$.By definition, acceleration $a = \frac{\Delta v}{\Delta t}$.Hence, the slope of the velocity-time graph equals the acceleration of the object.In contrast, the area under a velocity-time graph represents displacement, not acceleration.A distance-time graph's slope gives speed, while its area is not physically meaningful here.Therefore, acceleration is best determined from the slope of the velocity-time graph.Answer:C. slope of its velocity-time graph.