SSC CPO SI and ASI 2012 Paper

Question : 137 of 200

Marks: +1, -0

The angle of elevation of an aeroplane from a point on the ground is 60°. After 15 seconds of flight, the elevation changes to 30°. If the aeroplane is flying at a height of 1500

√ 3

m, find the speed of the plane.

300 m/sec
200 m/sec
100 m/sec
150 m/sec

Validate

Solution:

(2)

In ΔGHJ,

\tan 60^{\°}=\ {\ {HJ}}/{\ {GH}}⇒√{3}= {1500 \√{3}}/{\ {GH}}

⇒ GH =1500 m
In ΔGIK,

\tan 30^{\°}=\ {\ {IK}}/{ {GI}} ⇒{1}/{\√{3}}=\ {1500 \√{3}}/{\ {GI}}

⇒{Gl}=4500 {m}

Now, speed of plane is

{4500-1500}/{15}=\ {3000}/{15}=200 \

m/s

Go to Question:

Prev Question

Next Question