I You are driving down the road at 15.6 m/s (35 mph) when an ambu-
lance passes you with its siren blaring. The ambulance siren produces
a frequency of 700 Hz. As the ambulance approaches you from be-
hind, you hear a frequency of 740 Hz. (a) What is the speed of the am-
bulance? (b) What frequency do you hear after the ambulance passes?