wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

A man on top of a building observes a car at an angle of depression α, where tan α=15 and sees that it is moving towards the base of the building. Ten minutes later the angle of depression of the car is found to be β where tan β=5. If the car is moving with an uniform speed, then how much more time will it take to reach the base of the tower?

Open in App
Solution

Let 'h' be the height of the tower.
Let D be the point where the angle of depression from the top of the tower is α and C be the point where the angle of depression is β

tan α=15,tan β=5 ...... (given)

In Δ ABC

tan β=hx

5=hx

x=h5 (i)

In Δ ABD

tan α=hy

15=hy

y=h5 (ii)

To travel (y-x) i.e (h5h5) takes 10 minutes

To travel h5 will take

10(h5)h5h5

=10h55hh5

=10h4h=212 minutes


flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Angle of Elevation and Angle of Depression
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon