Question

aeroplane is flying at a constant height of 1200 root 3 the angle of elevation of an aeroplane from a point on the ground is 60 degree after a flight of 25 seconds the angle of elevation changes to 30 degree find the speed of aeroplane​

Answer 1

Answer:

.........................

Answer 2

let the constant height be AB
let speed = x
• CD = distance = speed*time
CD = x * 25
= 25x

consider triangle ABC
tan60 = AB/BC = 1200 root 3 divided by BC
root3 = 1200root3 / BC
BC root 3 = 1200 root 3
BC = 1200 //

Now consider traingle ABD
tan 30 = AB /BD
1/root3 = 1200root3 / BC+CD
= 1200 root3/ 1200+25x
1/root3 * 1200+ 25x = 1200root3
1200+25x = 1200root3 * root 3
1200+ 25x = 1200x3
1200+25x = 3600
25x = 2400
x = 2400/25
x = 96