3 answers
(click or scroll down)
What is the question? If it is how long John was in the air, that would be twice the length of time that it takes to fall 1 mile. I assume you can calculate that.
Have you ever heard of
X = (1/2) g t^2 ?
Do it in feet. g = 32.2 ft/s^2.
X = 5280 feet.
Don't forget to double t. The time going up equals the time coming down.