IIT JEE , AIEEE Forum - Physics , Mechanics

harsha_27

see let the velocity be v.

velocity of sound in air = c = 340m/s

now f1 = f { c / (c-v)}

f2 = f { c/(c+v)}

now given f1-f2 = 200Hz

=> 2fcv/(c²-v²) = 200

divide and multiply by v²....

2f (c/v)/[(c²/v²)-1] = 200

let c/v = x........

now 2fx/(x²-1) = 200

substituting f=2000Hz and simplifying.......

x²-20x-1 = 0

solving for x ......

x = 10 +

101

=> c/v = 10 +

101

=> v = 340(

101 - 10)

now v = Aw

=> w = v/A

=> w = 340(

101-10)/(50x10^-2)

=> w = 680(

101-10)

=> w

33.9 rad/sec

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