An aircraft is flying in a straight line away from a person standing on the ground. The initial angle of elevation changes from 70 degrees to 30 degrees in 1 minute. What is the cruising speed of the aircraft if its altitude is 10,000 m?

Answer 1

If x is the horizontal distance away (in km),

x/10 = cotθ
x = 10cotθ
x(70) = 3.63
x(30) = 17.32
so, the plane traveled 13.69km in 1 minute

speed is thus 13.69km/min