Question

an aeroplane flying at a height of 2500 root 3 m above that ground ; is observed to be at angle of elevation 60 from the ground. after a flight of 25 seconds the angel of elevation is 30. Find the speed of the plane in m/sec.

Answer 1

let A be the aeroplane in the diagram and after 25 sec its position is B.and EDC points are in ground.

let the speed of aeroplane be x m/s.so in 25 sec it will cover 25x meter.i.e DC = 25x.now follow the attachement