Suppose A and B in the previous problem change their positions in such a way that the line joining them becomes perpendicular to the direction of wind while maintaining the separation x. What will be the time lag B finds between seeing and hearing the drum beating by A?

Given:
Distance between A and B = x


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Let v be the velocity of sound in the direction along line AC.
Let u be the velocity of air in the direction along line AB.
Angle between v and u


Resultant velocity of sound and air that will reach B=


Here, the time taken by light to reach B is neglected.
Time lag between seeing and hearing = Time taken to hear the sound of the drum



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