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When some vehicle moves towards a stationary person, he finds difference in the frequency of horn by 2.5% of original frequency. If speed of sound is 320 m/s then, find speed of this vehicle.

Answer» <html><body><p>`8m//s`<br/>`<a href="https://interviewquestions.tuteehub.com/tag/800-338448" style="font-weight:bold;" target="_blank" title="Click to know more about 800">800</a> m//s`<br/>`7m//s`<br/>`80m//s`</p>Solution :<img src="https://doubtnut-static.s.llnwi.net/static/physics_images/KPK_AIO_PHY_XI_P2_C15_E06_015_S01.png" width="80%"/> <br/> We have, `(f _(L))/( <a href="https://interviewquestions.tuteehub.com/tag/v-722631" style="font-weight:bold;" target="_blank" title="Click to know more about V">V</a> + v _(L)) = (f _(S))/( v + v _(S))` <br/> Here if `f _(S) = <a href="https://interviewquestions.tuteehub.com/tag/100-263808" style="font-weight:bold;" target="_blank" title="Click to know more about 100">100</a> Hz,` then `f _(L) = 102.5 Hz` <br/> `<a href="https://interviewquestions.tuteehub.com/tag/therefore-706901" style="font-weight:bold;" target="_blank" title="Click to know more about THEREFORE">THEREFORE</a> ( 102.5)/(320+0) = (100)/(320 -v _(S))` <br/> `therefore 320 -v _(S) = (32000)/(102.5)` <br/> `therefore 320 - (32000)/(102.5) =v _(S)` <br/> `therefore v _(S) = ((320 xx 102.5) - 32000)/(102.5)` <br/> `v _(S) = (800)/( 102.5) = 7.<a href="https://interviewquestions.tuteehub.com/tag/8-336412" style="font-weight:bold;" target="_blank" title="Click to know more about 8">8</a> (m)/(s) ~~ 8 (m)/(s)`</body></html>


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