Question #b667f

2 Answers
Feb 17, 2018

the plane flies at height, h=3400m
angle subtended, θ=30

tanθ=distance travelled in 10sh
tan30=x3400
x=13×3400=0.58×3400=1972m

now, since
speed=distancetime
=197210=197.2ms

Feb 17, 2018

speed = 196.3 m/s

Explanation:

The basic formula you have to use will be
speed = distance travelled / time taken ;
Here we know the time as 10 second .
We have a distance of 3400 m but that is NOT the distance travelled

It is rather the height of the aircraft directly above the observer/observation point at a time enter image source here

The aircraft moves from point A to B in 10 seconds creating an angle of seperation 30 degrees at observation point O .

Using basic trigonometry , we can fin distance AB
From triangle ABO ,

tan30o=ABOA
=> AB=OAtan30
=> AB=34000.5773=1963

So distance AB = 1963 , time taken = 10s
Speed of the aircraft = 1963/10 = 196.3 m/s