A source of sound is allowed to fall freely from the top of a tower of height $$20$$ m. A frequency detector is placed on the ground at the base of the tower. If the frequency of sound emitted by the source is $$620$$ Hz, the apparent frequency recorded by the detector just before the source hits the ground is [velocity of sound in air $$=$$ $$330$$ $$m/s$$ and g $$=$$ $$10$$ $$m/s2$$]

Question

A source of sound is allowed to fall freely from the top of a tower of height $$20$$ m. A frequency detector is placed on the ground at the base of the tower. If the frequency of sound emitted by the source is $$620$$ Hz, the apparent frequency recorded by the detector just before the source hits the ground is [velocity of sound in air $$=$$ $$330$$ $$m/s$$ and g $$=$$ $$10$$ $$m/s2$$]

Infinity Learn · Accepted Answer

Velocity of the source just before it bits the ground $$u=2gH=2$$×$$10$$×$$20$$ $$m/s=20$$ $$m/s$$∴ $$f=f0(1$$−$$uv)=620(1$$−$$20330)Hz=660$$ Hz

Remember concepts with our Masterclasses.

Ready to Test Your Skills?

free study material