An airplane flying at an altitude of 40,000 feet passes directly over a fixed object on the ground. One minute later, the angle of depression of the object is 40°. Approximate the speed of the airplane to the nearest mile per hour.

Question

anonymous · Answer

tan40=40,000/d
d=40000/tan40=47,670.14 feet
now speed v =d/t
              47670.14  feet           1 mile          60 min
   v=     ------------     x   -----------  x  -----
                   1 min                 5280 feet        1 hour
  
     v= 541.71 mph  approx      ans..