Question

A plane is flying at the height of 40,000 ft above the sea level. At a particular point, it is exactly above a submarine floating 200 ft below the sea level.
(i) What is the vertical distance between them?
(ii) If the airport is 800 ft above sea level and the plane descends at the rate of 200 ft/sec, then find the total time required to touchdown

Answer 1

(i) Vertical height of plane from sea level = 40,000 ft
Vertical height of submarine below level = - 200 ft
Vertical height between plane and submarine = 40000 $–$($–$ 200) = 40200 ft
(ii) Descending rate of plane = 200 ft/min
Plane height from sea level = 40000 ft
Airport is 800 ft above sea level.
Therefore, total distance for touchdown = 40000 – 800 = 39200 ft
Time required to touchdown = 39200$/$200 = 196 sec