Aplane flies horizontally at an altitude of 7 km and passes directly over a tracking telescope on the ground. when the angle of elevation is π/4, this angle is decreasing at a rate of π/4 rad/min. how fast is the plane traveling at that time?

The plane moving with velocity =

Explanation:

Let  be angle of elevation and x(t)be the horizontal displacement of the plane  from the tracking slope

We are given that a plane flies horizontally at an altitude of 7 Km and passes directly over a tracking telescope on the ground .

The angle of elevation is

The rate at which an angle of elevation decreasing =-rad/min

Differentiate w.r.t time

Then we get

The plane moving with velocity =

d.7.5cm is your answer