Question

A train is moving with velocity v m/s blows whistle for t sec if speed of sound is c m/s . Find the duration for which the whistle is heard by a boy standing far away From train?

Answer 1

Answer:

name of the institution

Answer 2

Answer:

((c-v)t)/c

Explanation:

According to Doppler Effect ,

the frequency to the boy ,  

f ' = $(\frac{c}{c - v} )$ f                  (f - main frequency)

$\frac{1}{t'} = (\frac{c}{c - v} ) \frac{1}{t}$

t (time duration) = $(\frac{c - v}{c}) t$