Modern subsonic aircraft have been refined to such an extent that 75% of the parasite drag (portion of total aircraft drag not directly associated with producing lift) can be attributed to friction along the external surfaces. For atypical subsonic jet, the parasite drag coefficient based on wing area is 0.011. Determine the friction drag on such an aircraft 

a. At 500 mph at 35,000 ft 

b. At 200 mph at sea level The wing area is 2400 ft².