Super Challenge Problem Determined to test gravity, a student walks off the Burj Khalifa (aka really tall building) in Dubai, which is 829 m high, and falls freely. His initial velocity is zero. Jetpack Woman leaves the roof 5s later to save the student with an initial velocity downward and then is in free-fall. In order both to catch the student and to prevent injury to her, Jetpack Woman should catch the student at a sufficiently great height and arrive at the ground with zero velocity. The upward acceleration that accomplishes this is provided by Jetpack Woman's jet pack, which she turns on just as she catches the student; before then the student is in free-fall. To prevent discomfort to the student, the magnitude of the acceleration is limited to four times gravity (4g). (You may assume that Jetpack Woman has superpowers, which allow her to change velocity instantaneously.) How high above the ground must Jetpack Woman catch the student?