The angle of elevation of an aeroplane from a point A on the gro

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsShort Answer Type

171.

A man standing on the deck of a ship, which is 10 m above water level, observes the angle of elevation of the top of a hill as 60° and the angle of depression of the base of a hill as 30°. Find the distance of the hill from the ship and the height of the hill.

3152 Views

172.

The angle of elevation of the top Q of a vertical tower PQ from a point X on the ground is 60o. From a point Y, 40 m vertically above X, the angle of elevation of the top Q of the tower is 45o. Find the height of the tower PQ and the distance PX. Use square root of 3 space equals 1.73

4614 Views

173.

In Given figure, a tower AB is 20 m high and BC, its shadow on the ground, is m20 square root of 3 long. Find the sun's altitude.

2000 Views

Advertisement

174. The angle of elevation of an aeroplane from a point A on the ground 60°. After a flight of 15 seconds, the angle of elevation changes to 30°. If the aeroplane is flying at a constant height of 1500 space square root of 3 space end root space straight m, find the speed of the plane in km/hr.





Let P and Q be the two positions of the plane and A be the point of observation. Let ABC be the horizontal line through A. It is given that angles of elevation of the plane in two positions P and Q from a point A are 60° and 30°, respectively.

∴ ∠PAB = 60o and ∠QAC = 30o

Also comma space PB space equals space QC space equals space 1500 square root of 3 space straight m

In space increment ABP comma space we space have

tan space 60 degree space equals space BP over AB

rightwards double arrow space square root of 3 space equals space fraction numerator 1500 square root of 3 over denominator AB end fraction

rightwards double arrow space AB space equals space 1500 space straight m

In space increment ACQ comma space we space have space

tan space 30 degree space equals space QC over AC
rightwards double arrow space fraction numerator 1 over denominator square root of 3 end fraction space equals space fraction numerator 1500 square root of 3 over denominator AB end fraction

rightwards double arrow space AC space equals space 1500 space straight x space 3 space equals space 4500 space straight m

therefore space BC space equals space AC space minus space AB space equals space 4500 space straight m space minus space 1500 space straight m space equals space 3000 space straight m

Thus comma space the space plane space travels space 3000 space meters space in space 15 space second.

therefore space Speed space space of space the space plane

equals space 3000 over 15

equals space 20 space straight m divided by straight s
space
equals space fraction numerator 200 space straight x space 60 space straight x space 60 space over denominator 1000 end fraction

equals 720 space km divided by straight h

Hence comma space the space speed space of space the space plane space is space 720 space km divided by straight h.
1213 Views

Advertisement
Advertisement

 Multiple Choice QuestionsLong Answer Type

175. At a point A, 20 metres above the level of water in a lake, the angle of elevation of a cloud is 30°. The angle of depression of the reflection of the cloud in the lake, at A is 60°. Find the distance of the cloud from A.
2179 Views

 Multiple Choice QuestionsShort Answer Type

176.

The ratio of the height of a tower and the length of its shadow on the ground is √3:1. What is the angle of elevation of the sun?

18184 Views

177.

A moving boat is observed from the top of a 150 m high cliff moving away from the cliff. The angle of depression of the boat changes from 60° to 45° in 2 minutes. Find the speed of the boat in m/h.

7636 Views

 Multiple Choice QuestionsLong Answer Type

178.

The angle of elevation of a cloud from a point 60 m above the surface of the water of a lake is 30° and the angle of depression of its shadow in water of lake is 60°. Find the height of the cloud from the surface of the water. 

4138 Views

Advertisement

 Multiple Choice QuestionsShort Answer Type

179.

As observed from the top of a 100 m high light house from the sea-level, the angles of depression of two ships are 30° and 45°. If one ship is exactly behind the other on the same side of the light house, find the distance between the two ships. [ Use √3= 1.732 ]


 Multiple Choice QuestionsMultiple Choice Questions

180.

The angle of depression of a car, standing on the ground, from the top of a 75 m high tower, is 30o. The distance of the car from the base of the tower (in m.) is

  • 25√3

  • 50√3

  • 75√3

  • 150


Advertisement