You are standing on the road as a garbage truck recedes from you ata speed of 30 m/s. The trucks backup signal sound has a fixed frequency of 300 Hz. At the same time a another garbage truck is approaching you. The second truck is going at the same speed and has the same signal sound.
A) What frequencies do you hear from each garbage truck?
B) What is the frequency difference, if any, between the two observed frequencies?