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Last updated at May 29, 2018 by Teachoo
Transcript
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
Questions easy to difficult
Angle of Depression from point A to point B is same as Angle of Elevation from point B to point A
How to find Height when angle of elevation is given?
How to find Distance when angle of depression is given?
Example 1
EX 9.1, 4
EX 9.1, 5
EX 9.1, 3 Important
EX 9.1, 2 Important
Ex 9.1, 7
Example 4
Example 2 Important
EX 9.1, 8
Example 5
Ex 9.1, 11
Example 7 Important
Example 3 Important
Ex 9.1, 6 Important
EX 9.1, 9 Important
Ex 9.1, 10
Example 6 Important
Ex 9.1, 13 Important
Ex 9.1, 12 Important
Ex 9.1, 16 Important
Ex 9.1, 14 Important
Ex 9.1, 15 Important You are here
EX 9.1, 1
Questions easy to difficult
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