Amother hawk screeches as she dives at you. female hawks screech at 800 mhz. however, because she is diving toward you, you hear the screech at 900 hz. how fast is that hawk approaching?
a railroad crossing has been equipped with a loud alarm. as the train approaches the railroad crossing at 30 m/s on a very cold day, the train engineer hears the alarm with a frequency of 720 hz. after passing, the train engineer hears a frequency of 600 hz. what is the speed of sound in air on this particularly chilly day?
when i bought my dishwasher, the specifications said that the sound insulation on the unit lowered the sound intensity level by 42 decibels. (bwithout - bwith = 42 db.) by what fraction is the intensity of the sound reduced by the sound insulation?
the noise ordinance for the city of san luis obispo prohibits noise that can be heard 50 feet from your property line between 7 am and 10 pm. (50 feet ~ 17 a. what is the intensity of sound that can barely be heard? (recall that a sound that can barely be heard is 0 db.) b. if a stereo can barely be heard at a distance of 17 m, how many decibels is it at a distance of half a meter?