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Ex 9.1, 15 - A straight highway leads to foot of a tower - Questions easy to difficult

Ex 9.1, 15 - Chapter 9 Class 10 Some Applications of Trigonometry - Part 2
Ex 9.1, 15 - Chapter 9 Class 10 Some Applications of Trigonometry - Part 3
Ex 9.1, 15 - Chapter 9 Class 10 Some Applications of Trigonometry - Part 4

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Ex 9.1 , 15 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. Let the man & tower height be AD Given that man sees car first at an angle of depression of 30 So, PAB = 30 After 6 seconds, the man sees car at an angle of depression of 60 So, PAC = 60 Now, tower is vertical, So, ADB = 90 Also, From (1) & (2) 3 CD = / 3 3 ( 3 CD) = BD 3CD = BD 3CD = BC + CD 3CD CD = BC 2CD = BC CD = /2 Given that Time taken to cover BC = 6 seconds Time taken to cover /2 = 6/2 seconds = 3 seconds Time taken to cover CD = 3 seconds

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.