Question

In 3-5 sentences, summarize the balanced forces that are present when a soccer ball is resting on the ground, and the unbalanced forces that are present when a soccer ball is kicked and moves through the air or rolls on the ground.(4 points)

Answer 1

When a soccer ball rests on the ground, gravity pulls it downward and the ground supplies an equal and opposite normal force upward, so the forces are balanced and the net force is zero. When a player kicks the ball, the kick provides an unbalanced applied force that accelerates the ball. While flying, gravity (downward) and air resistance (opposite the motion) act; gravity causes downward acceleration and drag reduces its speed, so the net force is nonzero. When the ball rolls on the ground, gravity and the normal force remain balanced vertically but kinetic friction acts opposite the motion, producing an unbalanced horizontal force that slows the ball.