Gradient on a velocity–time graph gives acceleration; a horizontal section means constant velocity. For a falling object, drag increases with speed until it balances weight, giving zero resultant force and terminal velocity. Opening a parachute increases drag, causing deceleration until a lower terminal velocity is reached. Terminal-velocity graph interpretation is a Separate Physics extension. Example: Find acceleration from 4 m/s to 16 m/s in 6 s. 2 m/s². Use clear labels. Justify your answer.