question_answer

A person standing on an open ground hears the sound of a jet aeroplane, coming from north at an angle 60° with ground level. But he finds the aeroplane right vertically above his position. If v is the speed of sound, speed of the plane is [JEE Main 12-Jan-2019 Morning]

A) v

B) \[\frac{\sqrt{3}}{2}v\]

C) (c)\[\frac{2v}{\sqrt{3}}\]

D) (d)\[\frac{v}{2}\]

Correct Answer: D

Solution :

[d] \[{{v}_{p}}=v\,\cos {{60}^{o}}\]\[=\frac{v}{2}\]