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 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 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 

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) 

From the top of an upright pole $$24\sqrt { 3} $$ feet high, the angle of elevation of the top of an upright tower was 60⁰. If the foot of the pole was 60 feet away from the foot of the tower, what tall (in feet) was the tower?

The angles of elevation of the top of a temple, from the foot and the top of a building 48 m high, are 60^o and 30^o respectively. The height of the temple is more than the building. The height of the temple is-

A straight tree breaks due to storm and the broken part bends so that the top of the tree touches the ground making an angle of 30 ° with the ground. The distance from the foot of the tree to the point, where the top touches the ground is 10m. Find the total height of the tree 

The length of the shadow of a vertical tower on level ground increases by 10 meters when the altitude of the sun changes from 45° to 30°. Then the height of the tower is