Question

. A straight highway leads to the foot of a tower. A man standing at the top of the tower
observes a car at an angle of depression of 30°, which is approaching the foot of the
tower with a uniform speed. Six seconds later, the angle of depression of the car is found
to be 60°. Find the time taken by the car to reach the foot of the tower from this point,​

Answer 1

Answer:3 seconds

Step-by-step explanation:let CD=h

angle of depression=30

after 6 sec angle of depression=60

so let AB=y and BC=x

in triangle BCD

tan60=CD/BC

=h/x

h=x....(i)

in triangle ACD

tan30=CD/AC

1/=h/x+y

x+y=h

from eq(i)

x+y=()

x+y=3x....(ii)

It is given that a car moves from point A to B in 6 sec.

let speed =k km/s

time=distance/speed

6=y/k

y=6k

on putting y=6k in eq(ii)

x+6k=3x

6k=2x

x=3k

time=distance/speed

=x/k

=3k/k

=3 seconds

hope it helps!!! :)

Answer 2

Hope this will help you