An aeroplane at an altitude of 1km is flying horizontally at 800 km/hr passes directly over an observer. Find the rate at which it is approaching the observer when it is 1250 meters away from him.

A ladder 10 meter long is leaning against a vertical wall. If the bottom of the ladder is pulled horizontally away from the wall at the rate of 1.2 meters per second, find how fast the top of the ladder is sliding down the wall when the bottom is 6 meters away from the wall.

An aeroplane is flying at a constant horizontal velocity of 600 km/hr at an elevation of 6 km towards a point directly above the target on the earth's surface. At an appropriate time, the pilot releases a ball so that it strikes the target at the carth. The ball will appear to be falling

A man of height 2 meters walks at a uniform speed of 6 km/hr away from a lamp post of 6 meters high. Find the rate at which the length of the shadow is increasing.

A man of height 180 cm is moving away from a lamp post at the rate of 1.2 meters per second. If the height of the lamp post is 4.5 meters, find the rate at which the tip of the shadow is moving

A person standing on the bank of a river observes that the angle of elevation of the top of a tree standing on the opposite bank is 60^(@) . When he moves 40 m away from the bank, he finds the angle of elevation to be 30^(@) . Find the height of the tree and the width of the river. (sqrt3=1.73)

A train A is travelling at a speed of 108 km hr^(-1) . The train approaches another train B standing on the platform. The engine of the train B blows its hom. The frequency of the horn as observed by the driver in train A is 504 Hz. The frequency of the hom of train B is (speed of sound = 330 ms^(-1) )

Read the statements given below and identify the concepts explained in them. When Reema observes a light ray coming from medium 2 into medium 1, she sees that the ray bends away from the normal while entering the medium 1. Which medium in this case is optically rarer?