A runner is jogging in a straight line at a
steady v, 4.2 km/hr. When the runner is
L= 4.3 km from the finish line, a bird begins
flying straight from the runner to the finish
line at = 25.2 km/hr (6 times as fast as
the runner). When the bird reaches the finish
line, it turns around and flies directly back to
the runner.
