**The angle of elevation of a jet plane from a point A on the ground is 600.After a flight of 15 sec, … of 1500 √3 m,find the speed…**

###### Answers:

Let P and Q be the two positions of the plane and A be the point of observation. Let ABC be the horizontal line through A. It is given that angles of elevation of the plane in two positions P and Q from a point A are 60° and 30° respectively.

∴ ∠PAB = 60°, ∠QAB = 30°. It is also given that PB meters

In ΔABP, we have

In ΔACQ,we have

∴ Distance = BC = AC – AB = 4500m – 1500m = 3000m

Thus, the plane travels 3000m in 15 seconds

Hence speed of plane