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Waves and Sounds

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Doppler Effect: Racing a Train

WAVES-TUKXWF

Dave has just robbed a bank and is trying to escape the authorities by driving on the train tracks. He is driving at $80\: mph$ when he hears a train whistle with a frequency of $500\: Hz$ coming from behind him. A glance in his rear-view mirror shows that the train is $0.25\:mi$ behind him.