98.18: When a train is at rest, both a passenger on the train6h(m 5hvd)win and a ticket seller on the station agree that the trains whistle produces sound at a frequency of 120 Hz. When the train is moving away fih)6 wmh(n5dv rom the station at 15 m/s, the passenger hears a frequency of _____ Hz and the ticket seller hears a frequency of ____ Hz.

  08.18: A car is moving to the left at 20 m/s while a (c aj8iuwyog u06z6z)truck is moving to the right at 25 m/s. If the truck emits a sound of frequency 5000 Hz, what is the perceived frequency of the sound by the driver of the car? 86y)owu 0jg (iuzc6 azAssume the vehicles are moving directly away from each other on a $20.0^{\circ}C$ day

  17.39: A point wave source travels along the x-axis at constantt0k -e kbr+d ,rfyyd/. speed $v_s$. Stationary observers on the x-axis measure the wavelength of the waves that they receive. The ratio of the wavelength measured at a location behind the source to the wavelength measured at a location in front of the source is 1.50. If the wave speed is v, what is the source speed $v_s$?

  02.47: A car heads toward a brick5mh4 i6iogac8f fe1n8 wall in a crash test at 30 m/s. The horn is emitting a sound with frequency 250 Hz as it approaches the wall. If the air is still and the speed of sound in air is 340 m/s, what beat frequency from the horn would the driver of the cao6 8f 4mfgnc1ih85ie ar detect?