The boeing 747 is an air plane often equipped with four pratt and whitney jt9d engines that can each offer 193.50 kn of thrust. the air plane has a cruise speed of 907 km/hour, and typical cruise altitudes are of 11 km where the air temperature is -56 °c and density is 0.36 kg/m^3. its coefficient of drag at cruise conditions is 0.031, using the total wing area of 511m^2 as the reference area. its maximum take-off mass is 333000 kg a) what is the plane's coefficient of lift during cruise at its maximum take-off mass? b) what percentage of maximum thrust is required to keep the plane cruising? c) what is the plane's maximum angle of ascent? use the coefficient of lift calculated in part a). the following may be of : a cos(x) + bsin(x) = r cos(x-a) where r = va2+52 and a = tan(b/a)