Trigonometric Equations Question 151
Question: An aeroplane flying horizontally 1 km above the ground is observed at an elevation of 60o and after 10 seconds the elevation is observed to be $ 30^{o} $ . The uniform speed of the aeroplane in $ km/h $ is
[IIT 1965]
Options:
A) 240
B) $ 240\sqrt{3} $
C) $ 60\sqrt{3} $
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
- $ d=H\cot 30^{o}-H\cot 60^{o}; $ Time taken = 10 second Speed = $ \frac{\cot 30^{o}-\cot 60^{o}}{10}\times 60\times 60=240\sqrt{3} $ .
BETA
