Question

the angle of elevation of a jet plane from a point on a ground has measure 60 .
After a flight of 30 second . The angle of elevation has measure 30 . If the jet plane is flying at a constant height of 4500√3 m , find the speed of jet plane .

Answer 1

(Draw diagram based on gives conditions. mark E , D,C points down and A,B points up.)

Tan 60 = AD/ED

\sqrt3

3

= 1500\sqrt3

3

/ED

ED = 1500

Tan 30 = BC/EC

1/\sqrt3

3

= 1500√3/EC

DE = EC - ED

4500-1500

= 3000

PLANE TRAVELS 3000 m in 15 sec.

speed = Dstance/Time

= 3000/15

200 m/s.

Jet plane speed = 200m/s.