Question

An aeroplane is flying horizontally along a straight line at a height of 3000 m from the ground at a speed of 160 m/s. Find the time it would take for the angle of elevation of the plane as seen from a particular point on the ground to change from 60⁰ to 45⁰. Give your answer correct to the nearest second. with the figure​

Answer 1

Step-by-step explanation:

Solution

Let h eight of first aeroplane is BD which is flying t of sec BC=h m. dddLet angles of elevation from point A are 60

and 45

0

respectively.

So, ∠BAD=60

0

and ∠CAB=45

0

and Let AB=x m

From right angled ΔABD,

tan60

0

=

AB

BD

3

=

x

3000

From right angled ΔABC,

tan45

0

=

AB

BC

1=

x

h

1=

1000

3

h

h=1000

3

=1000∗1.732

=1732m

Hence, height of second plane from first plane

CD=BD–BC=3000–1732=1268 m