A paper leaf and a metal coin are both released from rest at the same height above the ground. The paper leaf takes much longer to reach the ground than the metal coin. Explain why the two objects do not reach the ground at the same time.

Both objects are released from rest, so the only force that can change their motion is gravity. The weight of each object is the same downward force, but the paper leaf has a much larger surface area relative to its mass than the metal coin. Consequently the air resistance acting upwards on the leaf is a larger fraction of its weight than the resistance on the coin. The net downward force on the leaf is therefore much smaller, giving it a smaller acceleration. The coin, with a much smaller air resistance, falls with an acceleration close to g and reaches the ground much sooner.