At the instant it passes through an altitude of 20,000 ft above sea level, what are the temperature, pressure, and density of the surrounding air? 2) At the instant it passes through an altitude of 20,000 ft above sea level, what are the time rate of change of the temperature, pressure, and density of the surrounding air? * Do the same for if the jet is in a rapid decent at a time rate of change of altitude of -15 ft/s.