A train standing on a platform is blowing a whistle of  frequency 400Hz calculate

1. Frequency

2. wave length

3. the speed of the sound as observed by a person standing a few meters away from the platform toward the observer with a speed of 10Ms-1

 

Asked by Aakrati Gawande | 26th Mar, 2014, 06:38: PM

Expert Answer:

f equals space 400 space H z S p e e d space o f space s o u n d comma space V space equals space 340 space m divided by s S p e e d space w. r. t. space s o u r c e space equals space 10 space m divided by s W h e n space t h e space t r a i n space a p p r o a c h e s space t h e space o b s e r v e r space w i t h space s p e e d space equals space 10 space m divided by s A p p a r e n t space f r e q u e n c y space equals space fraction numerator V over denominator V minus V subscript s end fraction f f apostrophe space equals fraction numerator 340 over denominator 340 minus 10 end fraction cross times 400 equals 412.1 space H z

Answered by  | 29th Mar, 2014, 01:24: PM

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