98.18: When a train is at rest,dcb u a4c00 z(wbju/g; both a passenger on the train and a ticket seller onb 0zu/(gu4dbccaj ; w0 the station agree that the trains whistle produces sound at a frequency of 120 Hz. When the train is moving away from 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*3n 4yz l;)k3iq,fl:h kyvaqw 20 m/s while a 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? Assume the vehicles are moving directly away from each ot k3 vl;iyl,z qfa3*qk) :nhy4wher on a $20.0^{\circ}C$ day

  17.39: A point wave source travels along0+,njxa.gkv 0( hz izz the x-axis at constant 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 brick wall in a crash test at 30 m/s. ;y mwu,i c/a-n res5gh) wo5 z-snn-q8The 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 th-) ,-n i5eco-/mws g5zwy a 8hsqnur;ne car detect?