In a speed-time graph, distance is represented by which feature?

• A. Area under the curve
• B. Height of the curve
• C. End value of the curve
• D. The slope of the curve

Answer: (A)

Area under the speed-time curve represents distance traveled. Each tiny interval of time contributes speed × small time, and adding those contributions across the whole journey is exactly the area under the curve. If speed is constant, that area is a rectangle with base (time) and height (speed), giving distance = speed × time. When speed changes, you still sum up many small pieces, and their total area gives the distance. The height of the curve shows instantaneous speed at that moment, not total distance; the end value is the final speed, and the slope reflects acceleration, not distance. So the distance corresponds to the area under the speed-time curve.