Motion — Determine

How can you tell from a distance-time or speed-time graph whether an object is at rest, moving at constant speed, accelerating, or decelerating?

(a) At rest: a horizontal (zero gradient) line on a distance-time graph, or a reading of zero on a speed-time graph. (b) Constant speed: a straight sloped line on a distance-time graph, or a horizontal line on a speed-time graph. (c) Accelerating: a distance-time graph curving with increasing gradient, or a speed-time graph sloping upward. (d) Decelerating: a distance-time graph curving with decreasing gradient, or a speed-time graph sloping downward.