Justin learns in physics that a feather and brick dropped from the same height should reach the ground at the same time since the gravitational acceleration of all objects is equivalent, but he does not believe his teacher, Dr. Tyler. He decides to drop a feather and a brick from several heights and record the time it takes for them to reach the ground in a table:

Justin's experiment worked! The brick fell faster than the feather. After Justin brings his findings to Dr. Tyler, she tells Justin that he is right because the drag, or air resistance, force is high on the feather but very low on the brick. She admits that, in class, problems and examples tend to make the simplifying assumption that there is no friction or drag.