The angle of elevation of an airplane from point A on the ground is 60°. After a flight of 10 seconds, on the same height, the angle of elevation from point A becomes 30°. If the airplane is flying at the speed of 720 km/hr, find the constant height at which the airplane is flying.
Given,
Assume BE = CD = h meter
Speed of the airplane = 720km/hr
= 720x5/18 = 200 m/sec
Time = 10 seconds
Distance covered (BC) = 200x10 = 2000 meter = ED
?