- When a skydiver jumps, their initial velocity is zero. - The primary force acting initially is gravity, causing downward acceleration approximately equal to g (acceleration due to gravity). The skydiver's velocity increases rapidly. - As the skydiver's velocity increases, air resistance (drag force) becomes significant. Drag force opposes the motion and increases with speed (often proportional to v or v²). - The net downward force is the difference between gravity and drag (F_net = mg - F_drag). The acceleration is F_net/m. - As speed increases, drag increases, so the net force decreases. This means the acceleration decreases over time. - The velocity continues to increase, but the rate of increase slows down. - Eventually, the drag force becomes equal in magnitude to the force of gravity. At this point, the net force is zero, and the acceleration is zero. The skydiver then falls at a constant velocity called terminal velocity. - A velocity-time graph for this motion would start at v=0, show the velocity increasing with a slope (acceleration) that decreases over time, and finally level off at the terminal velocity. Diagram (b) is the standard representation of this type of motion.