Question

a train moving towards a tunnel in a huge mountain with a spped o 12 m/sec sounds its whistle .if the driver hear 6 beats per sec & speed of sound in air is 332 m /sec find freq of Whislte​

Answer 1

Answer: The frequency of whistle is 6.225 beat /sec

Explanation:

Given that,

Frequency of source $f_{s} = 6 beat/sec$

Speed of sound v = 332 m/s

Speed of source $v_{s} = 12 m/s$

We know that,

$f = f_{s}\times \dfrac{v+ v_{o}}{v-v_{s}}$

$f = f_{s}\ beat/s\times \dfrac{332\ m/s+0}{332\ m/s-12m/s}$

$f = 6.225\ beat/sec$

Hence, the frequency of whistle is 6.225 beat /sec

Answer 2

But the answer is 80hz