Two helicopters X and Y are stationary at a distance of 80 m from each other and 10 m above the surface of sea (near the Antarctic).

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Two helicopters X and Y are stationary at a distance of 80 m from each other and 10 m above the surface of sea (near the Antarctic). The two helicopters have sound detectors. Helicopter X is stationary, vertically above a 50 m thick block of ice. (For the purpose of calculation, the vertical section of the block can be considered as rectangle). A Blue whale (W) is stationary vertically below X and 50 m below the water surface in such a way that there is no ice in the line of sight between Whale W and helicopter Y. This line of sight intersects water surface at point M.

Whale W gives out a call (sound) which is detected by X. Y received the same sound 0.07 seconds after X received it. (For practical purpose, helicopters are considered to be point objects).

(i) How much height of ice is floating above the surface of sea ?

(ii) What is the distance YM and YW ?

(iii) What is the time taken for the sound to travel from W to Y after W makes the sound ?

(iv) What is the time taken for the sound to travel from W to X ?

(v) What is the velocity of sound in the ice ?

+1 vote
answered by (70.1k points)
selected height of ice block outside the water = 9 % of 50 m = 4.5 m

Since density of ice = 910 kg/m3

& density of water = 1000 kg/m3 