98.18: When a train is at rest, both a passenger on the train an; u.zo:qz- - b3bthc /lg,aawsd 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 from the station at 15 m/s, thlgq,bzs3u hc--bo/.:zta ;aw e 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 tru*7vz1rhn j73nxur/gz a+y+ gick 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? Asszgyhngzivnr + 3a 7xr+/*u1j7ume the vehicles are moving directly away from each other on a $20.0^{\circ}C$ day

  17.39: A point wave source rh,* y 27 0(nrm11nrsnd/)d2br6w jkmumsh uatravels along 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 brick5tv*al;lf 1m4 vfelt5(cczg0 wall in a crash test at 30 m/s. The horn is emitting a sound with frequency 250 Hz as it approact1 c4 vm 5l5ealgf; c0t(fvlz*hes 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 car detect?