A train blowing its whistle moves with consta | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) Let $f_0$ be the actual frequency,$v$ be the speed of sound,and $v_s$ be the speed of the train.When the train approaches the observer,the apparen

Vedclass · Accepted Answer

$\frac{v}{5}$

Vedclass · Answer

(B) Let $f_0$ be the actual frequency,$v$ be the speed of sound,and $v_s$ be the speed of the train.When the train approaches the observer,the apparent frequency $f_A$ is given by: $f_A = \frac{v}{v - v_s} f_0$.The difference in frequency is $\Delta f_A = f_A - f_0 = \left( \frac{v}{v - v_s} - 1 \right) f_0 = \frac{v_s}{v - v_s} f_0$.When the train recedes from the observer,the apparent frequency $f_R$ is given by: $f_R = \frac{v}{v + v_s} f_0$.The difference in frequency is $\Delta f_R = f_0 - f_R = \left( 1 - \frac{v}{v + v_s} \right) f_0 = \frac{v_s}{v + v_s} f_0$.Given the ratio $\frac{\Delta f_A}{\Delta f_R} = \frac{3}{2}$,we have:$\frac{\frac{v_s}{v - v_s} f_0}{\frac{v_s}{v + v_s} f_0} = \frac{v + v_s}{v - v_s} = \frac{3}{2}$.Cross-multiplying gives: $2(v + v_s) = 3(v - v_s)$.$2v + 2v_s = 3v - 3v_s$.$5v_s = v$.$v_s = \frac{v}{5}$.

Similar Questions

$A$ sound source is moving towards a stationary listener with $1/10$th of the speed of sound. The ratio of apparent to real frequency is

$A$ source and a listener are both moving towards each other with a speed of $v/10$,where $v$ is the speed of sound. If the frequency of the note emitted by the source is $f$,the frequency heard by the listener would be nearly:

$A$ car moves towards a hill with speed $v_c$. It blows a horn of frequency $f$ which is heard by an observer following the car with speed $v_o$. The speed of sound in air is $v$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module