A plane that is flying horizontally at an altitude of 6 kilometers and a speed of 570 kilometers per hour passes directly over a radar station. How fast is the distance between the plane and the radar station increasing when the distance between the two is 14 kilometers

Answer 1

If the desired distance is z when the plane has moved x beyond the flyover point,

x^2+36=z^2

2x dx/dt = 2z dz/dt

Now just find x when z=14, and plug in the numbers to find dz/dt.