Question

A fighter plane is flying horizontally at a constant speed of 600km/hr and the pilot observes an oil drolling platform in the sea at an angle of depression 60degree,after flying in 30sec.in the same direction the pilot notices that the depression angle has become 45degree.calculate the alltitude of the plane above the sea level????live your answer in surd form

Answer 1

if the angle of depression is decreasing, then the plane is flying away from the platform.

30s * 600km/hr * 1hr/3600s = 5km

So, if you draw a diagram, you can see that if the plane's height is h km,

h cot45° - h cot60° = 5