Modenm commercial aiefinets are fargely made of ahaminum, a light and strong. metal, But the fect that alueninure is cheap enought that airplanes can be made out. of it is a bet of histoeical luck. Before the discovery of the Hall-Heroult process in 1586, aluminam nas as rare and expensive as gold, What woold happen if airplanes: had to be made of ateel? The furelage of the Deeing 747, which can carry 400 passengers, is approxmately a hollow alumunum cylander without ends, 70.7m tong. 6.5m wide; and 2.5mm thick (see thetch at right). Suppone this fuselage mas mede of seel (density 7.87gcm3 ) instesd of aluminum (density 2.70g/cm3 ), and lee's say the average passenger has a mass of 82.kg. We I alse assume the engines can't laft any greater mats than they alteady do. Calculate the mumbes of possengers that the Boeing 747 could carry if its fuselage was made of steel