This chapter is currently out of syllabus
1
JEE Main 2021 (Online) 25th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
A man is observing, from the top of a tower, a boat speeding towards the lower from a certain point A, with uniform speed. At that point, angle of depression of the boat with the man's eye is 30$$^\circ$$ (Ignore man's height). After sailing for 20 seconds, towards the base of the tower (which is at the level of water), the boat has reached a point B, where the angle of depression is 45$$^\circ$$. Then the time taken (in seconds) by the boat from B to reach the base of the tower is :
A
$$10(\sqrt 3 + 1)$$
B
$$10(\sqrt 3 - 1)$$
C
10
D
$$10\sqrt 3$$
2
JEE Main 2021 (Online) 24th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
The angle of elevation of a jet plane from a point A on the ground is 60$$^\circ$$. After a flight of 20 seconds at the speed of 432 km/hour, the angle of elevation changes to 30$$^\circ$$. If the jet plane is flying at a constant height, then its height is :
A
$$3600\sqrt 3 $$ m
B
$$1200\sqrt 3 $$ m
C
$$1800\sqrt 3 $$ m
D
$$2400\sqrt 3 $$ m
3
JEE Main 2021 (Online) 24th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
Two vertical poles are 150 m apart and the height of one is three times that of the other. If from the middle point of the line joining their feet, an observer finds the angles of elevation of their tops to be complementary, then the height of the shorter pole (in meters) is :
A
30
B
25
C
20$$\sqrt 3 $$
D
25$$\sqrt 3 $$
4
JEE Main 2020 (Online) 6th September Evening Slot
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
The angle of elevation of the summit of a mountain from a point on the ground is 45°. After climbing up one km towards the summit at an inclination of 30° from the ground, the angle of elevation of the summit is found to be 60°. Then the height (in km) of the summit from the ground is :
A
$${1 \over {\sqrt 3 - 1}}$$
B
$${{\sqrt 3 + 1} \over {\sqrt 3 - 1}}$$
C
$${1 \over {\sqrt 3 + 1}}$$
D
$${{\sqrt 3 - 1} \over {\sqrt 3 + 1}}$$
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