MY NOTES (a) What frequency is received by a person watching an oncoming ambulance moving at 120 km/h and emitting a steady 713 Hz sound from its siren? The speed of sound on this day is 345 m/s. Hz (b) What frequency does she receive after the ambulance has passed? Hz Supporting Materials Physical Constants You set a tuning fork into vibration at a frequency of 663 Hz and then drop it off the roof of the Physics building where the acceleration due to gravity is 9.80 m/s. Determine how far the tuning fork has fallen when sound waves emitted by the tuning work in the upward direction (i.e. back toward you) have a frequency of 631 Hz? (Take the speed of sound in air to be 343 m/s.) m Submit Answer