An ambulance traveling eastbound at 132.0 km/h with sirens blaring at a frequency of 7.50 ✕ 102 Hz passes cars traveling in both the eastbound and westbound directions at 59.0 km/h. (Assume the speed of sound is 343 m/s.) (a) What is the frequency observed by the eastbound drivers as the ambulance approaches from behind? (b) What is the frequency observed by the eastbound drivers after the ambulance passes them? (c) What is the frequency observed by the westbound drivers as the ambulance approaches them? (d) What is the frequency observed by the westbound drivers after the ambulance passes them?