A Navy captain going away from a lighthouse at the speed of 4[(73) -1] m/s. He observes that it takes him 1 minute to change the angle of elevation of the top of the lighthouse from 60 ° to 45 °. What is the height (in meters) of the lighthouse? 

A tower is broken at a point P above the ground. The top of the tower makes an angle 60 ° with the ground at Q. From another point R on the opposite side of Q angle of elevation of point P is 30 °. If QR = 180 m, then what is the total height (in meters ) of the tower ? 

The distance between two pillars is 120 meters. The height of one pillar is thrice of the other pillar. The angles of elevation of their tops from the midpoint of the line connecting their feet are complementary to each other. The height (in metres) of the pillar is (use : √3 = 1.732 )

A 1.6 m tall observer is 45 metres away from a tower. The angle of elevation from his eye to the top of the tower is 30 °, then the height of the tower in metres is ( Take √3 = 1.732 ) 

A helicopter, at an altitude of 1500 metre, finds that two ships are sailing towards it, in the same direction. The angles of depression of the ships as observed from the helicopter are 60° and 30° respectively. Distance between the two ships, in metre is

A boat is moving away from an observation tower. It makes an angle of depression of 60 ° with an observer's eye when at a distance of 50 m from the tower. After 8 sec, the angle of depression becomes 30 °. By assuming that it is running in still water, the approximate speed of the boat is 

An Aeroplan flying horizontally at a height of 3 km. Above the ground is observed at a certain point on earth to subtend an angle of 60 °. After 15 sec flight, its angle of elevation is changed to 30 °. The speed of the Aeroplan (taking √3 = 1.732) 

An observer on the top of a mountain, 500 m above the sea level, observes the angles of depression of the two boats in his same place vision to be 45 ° and 30 ° respectively. Then the distance between the boats, if the boats are on the same side of the mountain, is